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1 dpavlin 1 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
2     <html xmlns="http://www.w3.org/1999/xhtml">
3     <head>
4     <title>BackupPC</title>
5     <link rev="made" href="mailto:craig@atheros.com" />
6     </head>
7    
8     <body style="background-color: white">
9     <table border="0" width="100%" cellspacing="0" cellpadding="3">
10     <tr><td class="block" style="background-color: #cccccc" valign="middle">
11     <big><strong><span class="block">&nbsp;BackupPC</span></strong></big>
12     </td></tr>
13     </table>
14    
15     <p><a name="__index__"></a></p>
16     <!-- INDEX BEGIN -->
17    
18     <ul>
19    
20     <li><a href="#backuppc_introduction">BackupPC Introduction</a></li>
21     <ul>
22    
23     <li><a href="#overview">Overview</a></li>
24     <li><a href="#backup_basics">Backup basics</a></li>
25     <li><a href="#resources">Resources</a></li>
26     <li><a href="#road_map">Road map</a></li>
27     <li><a href="#you_can_help">You can help</a></li>
28     </ul>
29    
30     <li><a href="#installing_backuppc">Installing BackupPC</a></li>
31     <ul>
32    
33     <li><a href="#requirements">Requirements</a></li>
34     <li><a href="#how_much_disk_space_do_i_need">How much disk space do I need?</a></li>
35     <li><a href="#step_1__getting_backuppc">Step 1: Getting BackupPC</a></li>
36     <li><a href="#step_2__installing_the_distribution">Step 2: Installing the distribution</a></li>
37     <li><a href="#step_3__setting_up_config_pl">Step 3: Setting up config.pl</a></li>
38     <li><a href="#step_4__setting_up_the_hosts_file">Step 4: Setting up the hosts file</a></li>
39     <li><a href="#step_5__client_setup">Step 5: Client Setup</a></li>
40     <li><a href="#step_6__running_backuppc">Step 6: Running BackupPC</a></li>
41     <li><a href="#step_7__talking_to_backuppc">Step 7: Talking to BackupPC</a></li>
42     <li><a href="#step_8__cgi_interface">Step 8: CGI interface</a></li>
43     <li><a href="#how_backuppc_finds_hosts">How BackupPC Finds Hosts</a></li>
44     <li><a href="#other_installation_topics">Other installation topics</a></li>
45     <li><a href="#fixing_installation_problems">Fixing installation problems</a></li>
46     </ul>
47    
48     <li><a href="#restore_functions">Restore functions</a></li>
49     <ul>
50    
51     <li><a href="#cgi_restore_options">CGI restore options</a></li>
52     <li><a href="#commandline_restore_options">Command-line restore options</a></li>
53     </ul>
54    
55     <li><a href="#archive_functions">Archive functions</a></li>
56     <ul>
57    
58     <li><a href="#configuring_an_archive_host">Configuring an Archive Host</a></li>
59     <li><a href="#starting_an_archive">Starting an Archive</a></li>
60     </ul>
61    
62     <li><a href="#backuppc_design">BackupPC Design</a></li>
63     <ul>
64    
65     <li><a href="#some_design_issues">Some design issues</a></li>
66     <li><a href="#backuppc_operation">BackupPC operation</a></li>
67     <li><a href="#storage_layout">Storage layout</a></li>
68     <li><a href="#compressed_file_format">Compressed file format</a></li>
69     <li><a href="#rsync_checksum_caching">Rsync checksum caching</a></li>
70     <li><a href="#file_name_mangling">File name mangling</a></li>
71     <li><a href="#special_files">Special files</a></li>
72     <li><a href="#attribute_file_format">Attribute file format</a></li>
73     <li><a href="#optimizations">Optimizations</a></li>
74     <li><a href="#limitations">Limitations</a></li>
75     <li><a href="#security_issues">Security issues</a></li>
76     </ul>
77    
78     <li><a href="#configuration_file">Configuration File</a></li>
79     <ul>
80    
81     <li><a href="#modifying_the_main_configuration_file">Modifying the main configuration file</a></li>
82     <li><a href="#configuration_file_includes">Configuration file includes</a></li>
83     </ul>
84    
85     <li><a href="#configuration_parameters">Configuration Parameters</a></li>
86     <ul>
87    
88     <li><a href="#general_server_configuration">General server configuration</a></li>
89     <li><a href="#what_to_backup_and_when_to_do_it">What to backup and when to do it</a></li>
90     <li><a href="#general_perpc_configuration_settings">General per-PC configuration settings</a></li>
91     <li><a href="#email_reminders__status_and_messages">Email reminders, status and messages</a></li>
92     <li><a href="#cgi_user_interface_configuration_settings">CGI user interface configuration settings</a></li>
93     </ul>
94    
95     <li><a href="#version_numbers">Version Numbers</a></li>
96     <li><a href="#author">Author</a></li>
97     <li><a href="#copyright">Copyright</a></li>
98     <li><a href="#credits">Credits</a></li>
99     <li><a href="#license">License</a></li>
100     </ul>
101     <!-- INDEX END -->
102    
103     <hr />
104     <p>
105     </p>
106     <h1><a name="backuppc_introduction">BackupPC Introduction</a></h1>
107     <p>This documentation describes BackupPC version 2.1.0,
108     released on 20 Jun 2004.</p>
109     <p>
110     </p>
111     <h2><a name="overview">Overview</a></h2>
112     <p>BackupPC is a high-performance, enterprise-grade system for backing up
113     Unix, Linux and WinXX PCs, desktops and laptops to a server's disk.
114     BackupPC is highly configurable and easy to install and maintain.</p>
115     <p>Given the ever decreasing cost of disks and raid systems, it is now
116     practical and cost effective to backup a large number of machines onto
117     a server's local disk or network storage. For some sites this might be
118     the complete backup solution. For other sites additional permanent
119     archives could be created by periodically backing up the server to tape.</p>
120     <p>Features include:</p>
121     <ul>
122     <li>
123     A clever pooling scheme minimizes disk storage and disk I/O.
124     Identical files across multiple backups of the same or different PC
125     are stored only once (using hard links), resulting in substantial
126     savings in disk storage and disk writes.
127     <p></p>
128     <li>
129     Optional compression provides additional reductions in storage
130     (around 40%). The CPU impact of compression is low since only
131     new files (those not already in the pool) need to be compressed.
132     <p></p>
133     <li>
134     A powerful http/cgi user interface allows administrators to view log
135     files, configuration, current status and allows users to initiate and
136     cancel backups and browse and restore files from backups.
137     <p></p>
138     <li>
139     The http/cgi user interface has internationalization (i18n) support,
140     currently providing English, French, German, Spanish, Italian
141     and Dutch.
142     <p></p>
143     <li>
144     No client-side software is needed. On WinXX the standard smb
145     protocol is used to extract backup data. On linux or unix clients,
146     rsync or tar (over ssh/rsh/nfs) is used to extract backup data.
147     Alternatively, rsync can also be used on WinXX (using cygwin),
148     and Samba could be installed on the linux or unix client to
149     provide smb shares).
150     <p></p>
151     <li>
152     Flexible restore options. Single files can be downloaded from
153     any backup directly from the CGI interface. Zip or Tar archives
154     for selected files or directories from any backup can also be
155     downloaded from the CGI interface. Finally, direct restore to
156     the client machine (using smb or tar) for selected files or
157     directories is also supported from the CGI interface.
158     <p></p>
159     <li>
160     BackupPC supports mobile environments where laptops are only
161     intermittently connected to the network and have dynamic IP addresses
162     (DHCP). Configuration settings allow machines connected via slower WAN
163     connections (eg: dial up, DSL, cable) to not be backed up, even if they
164     use the same fixed or dynamic IP address as when they are connected
165     directly to the LAN.
166     <p></p>
167     <li>
168     Flexible configuration parameters allow multiple backups to be performed
169     in parallel, specification of which shares to backup, which directories
170     to backup or not backup, various schedules for full and incremental
171     backups, schedules for email reminders to users and so on. Configuration
172     parameters can be set system-wide or also on a per-PC basis.
173     <p></p>
174     <li>
175     Users are sent periodic email reminders if their PC has not
176     recently been backed up. Email content, timing and policies
177     are configurable.
178     <p></p>
179     <li>
180     BackupPC is Open Source software hosted by SourceForge.
181     <p></p></ul>
182     <p>
183     </p>
184     <h2><a name="backup_basics">Backup basics</a></h2>
185     <dl>
186     <dt><strong><a name="item_full_backup">Full Backup</a></strong><br />
187     </dt>
188     <dd>
189     A full backup is a complete backup of a share. BackupPC can be
190     configured to do a full backup at a regular interval (typically
191     weekly). BackupPC can be configured to keep a certain number
192     of full backups. Exponential expiry is also supported, allowing
193     full backups with various vintages to be kept (for example, a
194     settable number of most recent weekly fulls, plus a settable
195     number of older fulls that are 2, 4, 8, or 16 weeks apart).
196     </dd>
197     <p></p>
198     <dt><strong><a name="item_incremental_backup">Incremental Backup</a></strong><br />
199     </dt>
200     <dd>
201     An incremental backup is a backup of files that have changed (based on
202     their modification time) since the last successful full backup. For
203     SMB and tar, BackupPC backups all files that have changed since one
204     hour prior to the start of the last successful full backup. Rsync is
205     more clever: any files whose attributes have changed (ie: uid, gid,
206     mtime, modes, size) since the last full are backed up. Deleted, new
207     files and renamed files are detected by Rsync incrementals.
208     In constrast, SMB and tar incrementals are not able to detect deleted
209     files, renamed files or new files whose modification time is prior to
210     the last full dump.
211     </dd>
212     <dd>
213     <p>BackupPC can also be configured to keep a certain number of incremental
214     backups, and to keep a smaller number of very old incremental backups.
215     (BackupPC does not support multi-level incremental backups, although it
216     will in a future version.)</p>
217     </dd>
218     <dd>
219     <p>BackupPC's CGI interface ``fills-in'' incremental backups based on the
220     last full backup, giving every backup a ``full'' appearance. This makes
221     browsing and restoring backups easier.</p>
222     </dd>
223     <p></p>
224     <dt><strong><a name="item_partial_backup">Partial Backup</a></strong><br />
225     </dt>
226     <dd>
227     When a full backup fails or is canceled, and some files have already
228     been backed up, BackupPC keeps a partial backup containing just the
229     files that were backed up successfully. The partial backup is removed
230     when the next successful backup completes, or if another full backup
231     fails resulting in a newer partial backup. A failed full backup
232     that has not backed up any files, or any failed incremental backup,
233     is removed; no partial backup is saved in these cases.
234     </dd>
235     <dd>
236     <p>The partial backup may be browsed or used to restore files just like
237     a successful full or incremental backup.</p>
238     </dd>
239     <dd>
240     <p>With the rsync transfer method the partial backup is used to resume
241     the next full backup, avoiding the need to retransfer the file data
242     already in the partial backup.</p>
243     </dd>
244     <p></p>
245     <dt><strong><a name="item_identical_files">Identical Files</a></strong><br />
246     </dt>
247     <dd>
248     BackupPC pools identical files using hardlinks. By ``identical
249     files'' we mean files with identical contents, not necessary the
250     same permissions, ownership or modification time. Two files might
251     have different permissions, ownership, or modification time but
252     will still be pooled whenever the contents are identical. This
253     is possible since BackupPC stores the file meta-data (permissions,
254     ownership, and modification time) separately from the file contents.
255     </dd>
256     <p></p>
257     <dt><strong><a name="item_backup_policy">Backup Policy</a></strong><br />
258     </dt>
259     <dd>
260     Based on your site's requirements you need to decide what your backup
261     policy is. BackupPC is not designed to provide exact re-imaging of
262     failed disks. See <a href="#limitations">Limitations</a> for more information.
263     However, the addition of tar transport for linux/unix clients, plus
264     full support for special file types and unix attributes in v1.4.0
265     likely means an exact image of a linux/unix file system can be made.
266     </dd>
267     <dd>
268     <p>BackupPC saves backups onto disk. Because of pooling you can relatively
269     economically keep several weeks of old backups.</p>
270     </dd>
271     <dd>
272     <p>At some sites the disk-based backup will be adequate, without a
273     secondary tape backup. This system is robust to any single failure: if a
274     client disk fails or loses files, the BackupPC server can be used to
275     restore files. If the server disk fails, BackupPC can be restarted on a
276     fresh file system, and create new backups from the clients. The chance
277     of the server disk failing can be made very small by spending more money
278     on increasingly better RAID systems. However, there is still the risk
279     of catastrophic events like fires or earthquakes that can destroy
280     both the BackupPC server and the clients it is backing up if they
281     are physically nearby.</p>
282     </dd>
283     <dd>
284     <p>Some sites might choose to do periodic backups to tape or cd/dvd.
285     This backup can be done perhaps weekly using the archive function of
286     BackupPC.</p>
287     </dd>
288     <dd>
289     <p>Other users have reported success with removable disks to rotate the
290     BackupPC data drives, or using rsync to mirror the BackupPC data pool
291     offsite.</p>
292     </dd>
293     <p></p></dl>
294     <p>
295     </p>
296     <h2><a name="resources">Resources</a></h2>
297     <dl>
298     <dt><strong><a name="item_backuppc_home_page">BackupPC home page</a></strong><br />
299     </dt>
300     <dd>
301     The BackupPC Open Source project is hosted on SourceForge. The
302     home page can be found at:
303     </dd>
304     <dd>
305     <pre>
306     <a href="http://backuppc.sourceforge.net">http://backuppc.sourceforge.net</a></pre>
307     </dd>
308     <dd>
309     <p>This page has links to the current documentation, the SourceForge
310     project page and general information.</p>
311     </dd>
312     <p></p>
313     <dt><strong><a name="item_sourceforge_project">SourceForge project</a></strong><br />
314     </dt>
315     <dd>
316     The SourceForge project page is at:
317     </dd>
318     <dd>
319     <pre>
320     <a href="http://sourceforge.net/projects/backuppc">http://sourceforge.net/projects/backuppc</a></pre>
321     </dd>
322     <dd>
323     <p>This page has links to the current releases of BackupPC.</p>
324     </dd>
325     <p></p>
326     <dt><strong><a name="item_backuppc_faq">BackupPC FAQ</a></strong><br />
327     </dt>
328     <dd>
329     BackupPC has a FAQ at <a href="http://backuppc.sourceforge.net/faq">http://backuppc.sourceforge.net/faq</a>.
330     </dd>
331     <p></p>
332     <dt><strong><a name="item_mail_lists">Mail lists</a></strong><br />
333     </dt>
334     <dd>
335     Three BackupPC mailing lists exist for announcements (backuppc-announce),
336     developers (backuppc-devel), and a general user list for support, asking
337     questions or any other topic relevant to BackupPC (backuppc-users).
338     </dd>
339     <dd>
340     <p>The lists are archived on SourceForge and Gmane. The SourceForge lists
341     are not always up to date and the searching is limited, so Gmane is
342     a good alternative. See:</p>
343     </dd>
344     <dd>
345     <pre>
346     <a href="http://news.gmane.org/index.php?prefix=gmane.comp.sysutils.backup.backuppc">http://news.gmane.org/index.php?prefix=gmane.comp.sysutils.backup.backuppc</a>
347     <a href="http://sourceforge.net/mailarchive/forum.php?forum_id=503">http://sourceforge.net/mailarchive/forum.php?forum_id=503</a></pre>
348     </dd>
349     <dd>
350     <p>You can subscribe to these lists by visiting:</p>
351     </dd>
352     <dd>
353     <pre>
354     <a href="http://lists.sourceforge.net/lists/listinfo/backuppc-announce">http://lists.sourceforge.net/lists/listinfo/backuppc-announce</a>
355     <a href="http://lists.sourceforge.net/lists/listinfo/backuppc-users">http://lists.sourceforge.net/lists/listinfo/backuppc-users</a>
356     <a href="http://lists.sourceforge.net/lists/listinfo/backuppc-devel">http://lists.sourceforge.net/lists/listinfo/backuppc-devel</a></pre>
357     </dd>
358     <dd>
359     <p>The backuppc-announce list is moderated and is used only for
360     important announcements (eg: new versions). It is low traffic.
361     You only need to subscribe to one of backuppc-announce and
362     backuppc-users: backuppc-users also receives any messages on
363     backuppc-announce.</p>
364     </dd>
365     <dd>
366     <p>The backuppc-devel list is only for developers who are working on BackupPC.
367     Do not post questions or support requests there. But detailed technical
368     discussions should happen on this list.</p>
369     </dd>
370     <dd>
371     <p>To post a message to the backuppc-users list, send an email to</p>
372     </dd>
373     <dd>
374     <pre>
375     backuppc-users@lists.sourceforge.net</pre>
376     </dd>
377     <dd>
378     <p>Do not send subscription requests to this address!</p>
379     </dd>
380     <p></p>
381     <dt><strong><a name="item_other_programs_of_interest">Other Programs of Interest</a></strong><br />
382     </dt>
383     <dd>
384     If you want to mirror linux or unix files or directories to a remote server
385     you should consider rsync, <a href="http://rsync.samba.org">http://rsync.samba.org</a>. BackupPC now uses
386     rsync as a transport mechanism; if you are already an rsync user you
387     can think of BackupPC as adding efficient storage (compression and
388     pooling) and a convenient user interface to rsync.
389     </dd>
390     <dd>
391     <p>Unison is a utility that can do two-way, interactive, synchronization.
392     See <a href="http://www.cis.upenn.edu/~bcpierce/unison">http://www.cis.upenn.edu/~bcpierce/unison</a>.</p>
393     </dd>
394     <dd>
395     <p>Three popular open source packages that do tape backup are
396     Amanda (<a href="http://www.amanda.org">http://www.amanda.org</a>),
397     afbackup (<a href="http://sourceforge.net/projects/afbackup">http://sourceforge.net/projects/afbackup</a>), and
398     Bacula (<a href="http://www.bacula.org">http://www.bacula.org</a>).
399     Amanda can also backup WinXX machines to tape using samba.
400     These packages can be used as back ends to BackupPC to backup the
401     BackupPC server data to tape.</p>
402     </dd>
403     <dd>
404     <p>Various programs and scripts use rsync to provide hardlinked backups.
405     See, for example, Mike Rubel's site (<a href="http://www.mikerubel.org/computers/rsync_snapshots">http://www.mikerubel.org/computers/rsync_snapshots</a>),
406     JW Schultz's dirvish (<a href="http://www.pegasys.ws/dirvish">http://www.pegasys.ws/dirvish</a> (although as of
407     June 2004 this link doesn't work)),
408     Ben Escoto's rdiff-backup (<a href="http://rdiff-backup.stanford.edu">http://rdiff-backup.stanford.edu</a>),
409     and John Bowman's rlbackup (<a href="http://www.math.ualberta.ca/imaging/rlbackup">http://www.math.ualberta.ca/imaging/rlbackup</a>).</p>
410     </dd>
411     <dd>
412     <p>BackupPC provides many additional features, such as compressed storage,
413     hardlinking any matching files (rather than just files with the same name),
414     and storing special files without root privileges. But these other scripts
415     provide simple and effective solutions and are worthy of consideration.</p>
416     </dd>
417     <p></p></dl>
418     <p>
419     </p>
420     <h2><a name="road_map">Road map</a></h2>
421     <p>The new features planned for future releases of BackupPC
422     are at <a href="http://backuppc.sourceforge.net/faq/roadMap.html">http://backuppc.sourceforge.net/faq/roadMap.html</a>.</p>
423     <p>Comments and suggestions are welcome.</p>
424     <p>
425     </p>
426     <h2><a name="you_can_help">You can help</a></h2>
427     <p>BackupPC is free. I work on BackupPC because I enjoy doing it and I like
428     to contribute to the open source community.</p>
429     <p>BackupPC already has more than enough features for my own needs. The
430     main compensation for continuing to work on BackupPC is knowing that
431     more and more people find it useful. So feedback is certainly
432     appreciated, both positive and negative.</p>
433     <p>Beyond being a satisfied user and telling other people about it, everyone
434     is encouraged to add links to <a href="http://backuppc.sourceforge.net">http://backuppc.sourceforge.net</a>
435     (I'll see then via Google) or otherwise publicize BackupPC. Unlike
436     the commercial products in this space, I have a zero budget (in both
437     time and money) for marketing, PR and advertising, so it's up to
438     all of you! Feel free to vote for BackupPC at
439     <a href="http://freshmeat.net/projects/backuppc">http://freshmeat.net/projects/backuppc</a>.</p>
440     <p>Also, everyone is encouraged to contribute patches, bug reports, feature
441     and design suggestions, new code, FAQs, and documentation corrections or
442     improvements. Answering questions on the mail list is a big help too.</p>
443     <p>
444     <a href="#__index__"><small>Back to Top</small></a>
445     </p>
446     <hr />
447     <h1><a name="installing_backuppc">Installing BackupPC</a></h1>
448     <p>
449     </p>
450     <h2><a name="requirements">Requirements</a></h2>
451     <p>BackupPC requires:</p>
452     <ul>
453     <li>
454     A linux, solaris, or unix based server with a substantial amount of free
455     disk space (see the next section for what that means). The CPU and disk
456     performance on this server will determine how many simultaneous backups
457     you can run. You should be able to run 4-8 simultaneous backups on a
458     moderately configured server.
459     <p>Several users have reported significantly better performance using
460     reiser compared to ext3 for the BackupPC data file system. It is
461     also recommended you consider either an LVM or raid setup (either
462     in HW or SW; eg: 3Ware RAID5) so that you can expand the
463     file system as necessary.</p>
464     <p>When BackupPC starts with an empty pool, all the backup data will be
465     written to the pool on disk. After more backups are done, a higher
466     percentage of incoming files will already be in the pool. BackupPC is
467     able to avoid writing to disk new files that are already in the pool.
468     So over time disk writes will reduce significantly (by perhaps a factor
469     of 20 or more), since eventually 95% or more of incoming backup files
470     are typically in the pool. Disk reads from the pool are still needed to
471     do file compares to verify files are an exact match. So, with a mature
472     pool, if a relatively fast client generates data at say 1MB/sec, and you
473     run 4 simultaneous backups, there will be an average server disk load of
474     about 4MB/sec reads and 0.2MB/sec writes (assuming 95% of the incoming
475     files are in the pool). These rates will be perhaps 40% lower if
476     compression is on.</p>
477     <p></p>
478     <li>
479     Perl version 5.6.0 or later. BackupPC has been tested with
480     version 5.6.x, and 5.8.x. If you don't have perl, please
481     see <a href="http://www.cpan.org">http://www.cpan.org</a>.
482     <p></p>
483     <li>
484     Perl modules Compress::Zlib, Archive::Zip and File::RsyncP. Try ``perldoc
485     Compress::Zlib'' and ``perldoc Archive::Zip'' to see if you have these
486     modules. If not, fetch them from <a href="http://www.cpan.org">http://www.cpan.org</a> and see the
487     instructions below for how to build and install them.
488     <p>The File::RsyncP module is available from <a href="http://perlrsync.sourceforge.net">http://perlrsync.sourceforge.net</a>
489     or CPAN. You'll need to install the File::RsyncP module if you want to use
490     Rsync as a transport method.</p>
491     <p></p>
492     <li>
493     If you are using smb to backup WinXX machines you need smbclient and
494     nmblookup from the samba package. You will also need nmblookup if
495     you are backing up linux/unix DHCP machines. See <a href="http://www.samba.org">http://www.samba.org</a>.
496     Version 2.2.0 or later of Samba is required.
497     Samba versions 3.x are stable and now recommended instead of 2.x.
498     <p>See <a href="http://www.samba.org">http://www.samba.org</a> for source and binaries. It's pretty easy to
499     fetch and compile samba, and just grab smbclient and nmblookup, without
500     doing the installation. Alternatively, <a href="http://www.samba.org">http://www.samba.org</a> has binary
501     distributions for most platforms.</p>
502     <p></p>
503     <li>
504     If you are using tar to backup linux/unix machines you should have version
505     1.13.7 at a minimum, with version 1.13.20 or higher recommended. Use
506     ``tar --version'' to check your version. Various GNU mirrors have the newest
507     versions of tar, see for example <a href="http://www.funet.fi/pub/gnu/alpha/gnu/tar">http://www.funet.fi/pub/gnu/alpha/gnu/tar</a>.
508     As of June 2003 the latest version is 1.13.25.
509     <p></p>
510     <li>
511     If you are using rsync to backup linux/unix machines you should have
512     version 2.5.5 or higher on each client machine. See
513     <a href="http://rsync.samba.org">http://rsync.samba.org</a>. Use ``rsync --version'' to check your version.
514     <p>For BackupPC to use Rsync you will also need to install the perl
515     File::RsyncP module, which is available from
516     <a href="http://perlrsync.sourceforge.net">http://perlrsync.sourceforge.net</a>.
517     Version 0.52 or later is required.</p>
518     <p></p>
519     <li>
520     The Apache web server, see <a href="http://www.apache.org">http://www.apache.org</a>, preferably built
521     with mod_perl support.
522     <p></p></ul>
523     <p>
524     </p>
525     <h2><a name="how_much_disk_space_do_i_need">How much disk space do I need?</a></h2>
526     <p>Here's one real example for an environment that is backing up 65 laptops
527     with compression off. Each full backup averages 3.2GB. Each incremental
528     backup averages about 0.2GB. Storing one full backup and two incremental
529     backups per laptop is around 240GB of raw data. But because of the
530     pooling of identical files, only 87GB is used. This is without
531     compression.</p>
532     <p>Another example, with compression on: backing up 95 laptops, where
533     each backup averages 3.6GB and each incremental averages about 0.3GB.
534     Keeping three weekly full backups, and six incrementals is around
535     1200GB of raw data. Because of pooling and compression, only 150GB
536     is needed.</p>
537     <p>Here's a rule of thumb. Add up the disk usage of all the machines you
538     want to backup (210GB in the first example above). This is a rough
539     minimum space estimate that should allow a couple of full backups and at
540     least half a dozen incremental backups per machine. If compression is on
541     you can reduce the storage requirements by maybe 30-40%. Add some margin
542     in case you add more machines or decide to keep more old backups.</p>
543     <p>Your actual mileage will depend upon the types of clients, operating
544     systems and applications you have. The more uniform the clients and
545     applications the bigger the benefit from pooling common files.</p>
546     <p>For example, the Eudora email tool stores each mail folder in a separate
547     file, and attachments are extracted as separate files. So in the sadly
548     common case of a large attachment emailed to many recipients, Eudora
549     will extract the attachment into a new file. When these machines are
550     backed up, only one copy of the file will be stored on the server, even
551     though the file appears in many different full or incremental backups. In
552     this sense Eudora is a ``friendly'' application from the point of view of
553     backup storage requirements.</p>
554     <p>An example at the other end of the spectrum is Outlook. Everything
555     (email bodies, attachments, calendar, contact lists) is stored in a
556     single file, which often becomes huge. Any change to this file requires
557     a separate copy of the file to be saved during backup. Outlook is even
558     more troublesome, since it keeps this file locked all the time, so it
559     cannot be read by smbclient whenever Outlook is running. See the
560     <a href="#limitations">Limitations</a> section for more discussion of this problem.</p>
561     <p>In addition to total disk space, you shold make sure you have
562     plenty of inodes on your BackupPC data partition. Some users have
563     reported running out of inodes on their BackupPC data partition.
564     So even if you have plenty of disk space, BackupPC will report
565     failures when the inodes are exhausted. This is a particular
566     problem with ext2/ext3 file systems that have a fixed number of
567     inodes when the file system is built. Use ``df -i'' to see your
568     inode usage.</p>
569     <p>
570     </p>
571     <h2><a name="step_1__getting_backuppc">Step 1: Getting BackupPC</a></h2>
572     <p>Some linux distributions now include BackupPC. The Debian
573     distribution, supprted by Ludovic Drolez, can be found at
574     <a href="http://packages.debian.org/backuppc">http://packages.debian.org/backuppc</a>; it should be included
575     in the next stable Debian release. On Debian, BackupPC can
576     be installed with the command:</p>
577     <pre>
578     apt-get install backuppc</pre>
579     <p>In the future there might be packages for Gentoo and other
580     linux flavors. If the packaged version is older than the
581     released version then you will probably want to install the
582     lastest version as described below.</p>
583     <p>Otherwise, manually fetching and installing BackupPC is easy.
584     Start by downloading the latest version from
585     <a href="http://backuppc.sourceforge.net">http://backuppc.sourceforge.net</a>. Hit the ``Code'' button,
586     then select the ``backuppc'' or ``backuppc-beta'' package and
587     download the latest version.</p>
588     <p>
589     </p>
590     <h2><a name="step_2__installing_the_distribution">Step 2: Installing the distribution</a></h2>
591     <p>First off, there are three perl modules you should install.
592     These are all optional, but highly recommended:</p>
593     <dl>
594     <dt><strong><a name="item_compress_3a_3azlib">Compress::Zlib</a></strong><br />
595     </dt>
596     <dd>
597     To enable compression, you will need to install Compress::Zlib
598     from <a href="http://www.cpan.org">http://www.cpan.org</a>.
599     You can run ``perldoc Compress::Zlib'' to see if this module is installed.
600     </dd>
601     <p></p>
602     <dt><strong><a name="item_archive_3a_3azip">Archive::Zip</a></strong><br />
603     </dt>
604     <dd>
605     To support restore via Zip archives you will need to install
606     Archive::Zip, also from <a href="http://www.cpan.org">http://www.cpan.org</a>.
607     You can run ``perldoc Archive::Zip'' to see if this module is installed.
608     </dd>
609     <p></p>
610     <dt><strong><a name="item_file_3a_3arsyncp">File::RsyncP</a></strong><br />
611     </dt>
612     <dd>
613     To use rsync and rsyncd with BackupPC you will need to install File::RsyncP.
614     You can run ``perldoc File::RsyncP'' to see if this module is installed.
615     File::RsyncP is available from <a href="http://perlrsync.sourceforge.net">http://perlrsync.sourceforge.net</a>.
616     Version 0.52 or later is required.
617     </dd>
618     <p></p></dl>
619     <p>To build and install these packages, fetch the tar.gz file and
620     then run these commands:</p>
621     <pre>
622     tar zxvf Archive-Zip-1.01.tar.gz
623     cd Archive-Zip-1.01
624     perl Makefile.PL
625     make
626     make test
627     make install</pre>
628     <p>The same sequence of commands can be used for each module.</p>
629     <p>Now let's move onto BackupPC itself. After fetching
630     BackupPC-2.1.0.tar.gz, run these commands as root:</p>
631     <pre>
632     tar zxf BackupPC-2.1.0.tar.gz
633     cd BackupPC-2.1.0
634     perl configure.pl</pre>
635     <p>In the future this release might also have patches available on the
636     SourceForge site. These patch files are text files, with a name of
637     the form</p>
638     <pre>
639     BackupPC-2.1.0plN.diff</pre>
640     <p>where N is the patch level, eg: pl5 is patch-level 5. These
641     patch files are cumulative: you only need apply the last patch
642     file, not all the earlier patch files. If a patch file is
643     available, eg: BackupPC-2.1.0pl5.diff, you should apply
644     the patch after extracting the tar file:</p>
645     <pre>
646     # fetch BackupPC-2.1.0.tar.gz
647     # fetch BackupPC-2.1.0pl5.diff
648     tar zxf BackupPC-2.1.0.tar.gz
649     cd BackupPC-2.1.0
650     patch -p0 &lt; ../BackupPC-2.1.0pl5.diff
651     perl configure.pl</pre>
652     <p>A patch file includes comments that describe that bug fixes
653     and changes. Feel free to review it before you apply the patch.</p>
654     <p>The configure.pl script also accepts command-line options if you
655     wish to run it in a non-interactive manner. It has self-contained
656     documentation for all the command-line options, which you can
657     read with perldoc:</p>
658     <pre>
659     perldoc configure.pl</pre>
660     <p>When you run configure.pl you will be prompted for the full paths
661     of various executables, and you will be prompted for the following
662     information:</p>
663     <dl>
664     <dt><strong><a name="item_backuppc_user">BackupPC User</a></strong><br />
665     </dt>
666     <dd>
667     It is best if BackupPC runs as a special user, eg backuppc, that has
668     limited privileges. It is preferred that backuppc belongs to a system
669     administrator group so that sys admin members can browse backuppc files,
670     edit the configuration files and so on. Although configurable, the
671     default settings leave group read permission on pool files, so make
672     sure the BackupPC user's group is chosen restrictively.
673     </dd>
674     <dd>
675     <p>On this installation, this is __BACKUPPCUSER__.</p>
676     </dd>
677     <p></p>
678     <dt><strong><a name="item_data_directory">Data Directory</a></strong><br />
679     </dt>
680     <dd>
681     You need to decide where to put the data directory, below which
682     all the BackupPC data is stored. This needs to be a big file system.
683     </dd>
684     <dd>
685     <p>On this installation, this is __TOPDIR__.</p>
686     </dd>
687     <p></p>
688     <dt><strong><a name="item_install_directory">Install Directory</a></strong><br />
689     </dt>
690     <dd>
691     You should decide where the BackupPC scripts, libraries and documentation
692     should be installed, eg: /opt/local/BackupPC.
693     </dd>
694     <dd>
695     <p>On this installation, this is __INSTALLDIR__.</p>
696     </dd>
697     <p></p>
698     <dt><strong><a name="item_cgi_bin_directory">CGI bin Directory</a></strong><br />
699     </dt>
700     <dd>
701     You should decide where the BackupPC CGI script resides. This will
702     usually below Apache's cgi-bin directory.
703     </dd>
704     <dd>
705     <p>On this installation, this is __CGIDIR__.</p>
706     </dd>
707     <p></p>
708     <dt><strong><a name="item_apache_image_directory">Apache image directory</a></strong><br />
709     </dt>
710     <dd>
711     A directory where BackupPC's images are stored so that Apache can
712     serve them. This should be somewhere under Apache's DocumentRoot
713     directory.
714     </dd>
715     <p></p></dl>
716     <p>
717     </p>
718     <h2><a name="step_3__setting_up_config_pl">Step 3: Setting up config.pl</a></h2>
719     <p>After running configure.pl, browse through the config file,
720     __INSTALLDIR__/conf/config.pl, and make sure all the default settings
721     are correct. In particular, you will need to decide whether to use
722     smb, tar or rsync transport (or whether to set it on a per-PC basis)
723     and set the relevant parameters for that transport method.
724     See the section <a href="#step_5__client_setup">Client Setup</a> for more details.</p>
725     <p>
726     </p>
727     <h2><a name="step_4__setting_up_the_hosts_file">Step 4: Setting up the hosts file</a></h2>
728     <p>The file __TOPDIR__/conf/hosts contains the list of clients to backup.
729     BackupPC reads this file in three cases:</p>
730     <ul>
731     <li>
732     Upon startup.
733     <p></p>
734     <li>
735     When BackupPC is sent a HUP (-1) signal. Assuming you installed the
736     init.d script, you can also do this with ``/etc/init.d/backuppc reload''.
737     <p></p>
738     <li>
739     When the modification time of the hosts file changes. BackupPC
740     checks the modification time once during each regular wakeup.
741     <p></p></ul>
742     <p>Whenever you change the hosts file (to add or remove a host) you can
743     either do a kill -HUP BackupPC_pid or simply wait until the next regular
744     wakeup period.</p>
745     <p>Each line in the hosts file contains three fields, separated
746     by white space:</p>
747     <dl>
748     <dt><strong><a name="item_host_name">Host name</a></strong><br />
749     </dt>
750     <dd>
751     This is typically the host name or NetBios name of the client machine
752     and should be in lower case. The host name can contain spaces (escape
753     with a backslash), but it is not recommended.
754     </dd>
755     <dd>
756     <p>Please read the section <a href="#how_backuppc_finds_hosts">How BackupPC Finds Hosts</a>.</p>
757     </dd>
758     <dd>
759     <p>In certain cases you might want several distinct clients to refer
760     to the same physical machine. For example, you might have a database
761     you want to backup, and you want to bracket the backup of the database
762     with shutdown/restart using <a href="#item_%24conf%7bdumppreusercmd%7d">$Conf{DumpPreUserCmd}</A> and <a href="#item_%24conf%7bdumppostusercmd%7d">$Conf{DumpPostUserCmd}</A>.
763     But you also want to backup the rest of the machine while the database
764     is still running. In the case you can specify two different clients in
765     the host file, using any mnemonic name (eg: myhost_mysql and myhost), and
766     use <a href="#item_%24conf%7bclientnamealias%7d">$Conf{ClientNameAlias}</A> in myhost_mysql's config.pl to specify the
767     real host name of the machine.</p>
768     </dd>
769     <p></p>
770     <dt><strong><a name="item_dhcp_flag">DHCP flag</a></strong><br />
771     </dt>
772     <dd>
773     Starting with v2.0.0 the way hosts are discovered has changed and now
774     in most cases you should specify 0 for the DHCP flag, even if the host
775     has a dynamically assigned IP address.
776     Please read the section <a href="#how_backuppc_finds_hosts">How BackupPC Finds Hosts</a>
777     to understand whether you need to set the DHCP flag.
778     </dd>
779     <dd>
780     <p>You only need to set DHCP to 1 if your client machine doesn't
781     respond to the NetBios multicast request:</p>
782     </dd>
783     <dd>
784     <pre>
785     nmblookup myHost</pre>
786     </dd>
787     <dd>
788     <p>but does respond to a request directed to its IP address:</p>
789     </dd>
790     <dd>
791     <pre>
792     nmblookup -A W.X.Y.Z</pre>
793     </dd>
794     <dd>
795     <p>If you do set DHCP to 1 on any client you will need to specify the range of
796     DHCP addresses to search is specified in <a href="#item_%24conf%7bdhcpaddressranges%7d">$Conf{DHCPAddressRanges}</A>.</p>
797     </dd>
798     <dd>
799     <p>Note also that the <a href="#item_%24conf%7bclientnamealias%7d">$Conf{ClientNameAlias}</A> feature does not work for
800     clients with DHCP set to 1.</p>
801     </dd>
802     <p></p>
803     <dt><strong><a name="item_user_name">User name</a></strong><br />
804     </dt>
805     <dd>
806     This should be the unix login/email name of the user who ``owns'' or uses
807     this machine. This is the user who will be sent email about this
808     machine, and this user will have permission to stop/start/browse/restore
809     backups for this host. Leave this blank if no specific person should
810     receive email or be allowed to stop/start/browse/restore backups
811     for this host. Administrators will still have full permissions.
812     </dd>
813     <p></p>
814     <dt><strong><a name="item_more_users">More users</a></strong><br />
815     </dt>
816     <dd>
817     Additional user names, separate by commas and with no white space,
818     can be specified. These users will also have full permission in
819     the CGI interface to stop/start/browse/restore backups for this host.
820     These users will not be sent email about this host.
821     </dd>
822     <p></p></dl>
823     <p>The first non-comment line of the hosts file is special: it contains
824     the names of the columns and should not be edited.</p>
825     <p>Here's a simple example of a hosts file:</p>
826     <pre>
827     host dhcp user moreUsers
828     farside 0 craig jim,dave
829     larson 1 gary andy</pre>
830     <p>
831     </p>
832     <h2><a name="step_5__client_setup">Step 5: Client Setup</a></h2>
833     <p>Two methods for getting backup data from a client are supported: smb and
834     tar. Smb or rsync are the preferred methods for WinXX clients and rsync or
835     tar are the preferred methods for linux/unix clients.</p>
836     <p>The transfer method is set using the <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> configuration
837     setting. If you have a mixed environment (ie: you will use smb for some
838     clients and tar for others), you will need to pick the most common
839     choice for <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> for the main config.pl file, and then
840     override it in the per-PC config file for those hosts that will use
841     the other method. (Or you could run two completely separate instances
842     of BackupPC, with different data directories, one for WinXX and the
843     other for linux/unix, but then common files between the different
844     machine types will duplicated.)</p>
845     <p>Here are some brief client setup notes:</p>
846     <dl>
847     <dt><strong><a name="item_winxx">WinXX</a></strong><br />
848     </dt>
849     <dd>
850     The preferred setup for WinXX clients is to set <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> to ``smb''.
851     (Actually, for v2.0.0, rsyncd is the better method for WinXX if you are
852     prepared to run rsync/cygwin on your WinXX client. More information
853     about this will be provided via the FAQ.)
854     </dd>
855     <dd>
856     <p>If you want to use rsyncd for WinXX clients you can find a pre-packaged
857     zip file on <a href="http://backuppc.sourceforge.net">http://backuppc.sourceforge.net</a>. The package is called
858     cygwin-rsync. It contains rsync.exe, template setup files and the
859     minimal set of cygwin libraries for everything to run. The README file
860     contains instructions for running rsync as a service, so it starts
861     automatically everytime you boot your machine.</p>
862     </dd>
863     <dd>
864     <p>If you build your own rsync, for rsync 2.6.2 it is strongly
865     recommended you apply the patch in the cygwin-rsync package on
866     <a href="http://backuppc.sourceforge.net">http://backuppc.sourceforge.net</a>. This patch adds the --checksum-seed
867     option for checksum caching, and also sends all errors to the client,
868     which is important so BackupPC can log all file access errors.</p>
869     </dd>
870     <dd>
871     <p>Otherwise, to use SMB, you need to create shares for the data you want
872     to backup. Open ``My Computer'', right click on the drive (eg: C), and
873     select ``Sharing...'' (or select ``Properties'' and select the ``Sharing''
874     tab). In this dialog box you can enable sharing, select the share name
875     and permissions. Many machines will be configured by default to share
876     the entire C drive as C$ using the administrator password.</p>
877     </dd>
878     <dd>
879     <p>If this machine uses DHCP you will also need to make sure the
880     NetBios name is set. Go to Control Panel|System|Network Identification
881     (on Win2K) or Control Panel|System|Computer Name (on WinXP).
882     Also, you should go to Control Panel|Network Connections|Local Area
883     Connection|Properties|Internet Protocol (TCP/IP)|Properties|Advanced|WINS
884     and verify that NetBios is not disabled.</p>
885     </dd>
886     <dd>
887     <p>The relevant configuration settings are <a href="#item_%24conf%7bsmbsharename%7d">$Conf{SmbShareName}</A>,
888     <a href="#item_%24conf%7bsmbshareusername%7d">$Conf{SmbShareUserName}</A>, <a href="#item_%24conf%7bsmbsharepasswd%7d">$Conf{SmbSharePasswd}</A>, <a href="#item_%24conf%7bsmbclientpath%7d">$Conf{SmbClientPath}</A>,
889     <a href="#item_%24conf%7bsmbclientfullcmd%7d">$Conf{SmbClientFullCmd}</A>, <a href="#item_%24conf%7bsmbclientincrcmd%7d">$Conf{SmbClientIncrCmd}</A> and
890     <a href="#item_%24conf%7bsmbclientrestorecmd%7d">$Conf{SmbClientRestoreCmd}</A>.</p>
891     </dd>
892     <dd>
893     <p>BackupPC needs to know the smb share user name and password for a
894     client machine that uses smb. The user name is specified in
895     <a href="#item_%24conf%7bsmbshareusername%7d">$Conf{SmbShareUserName}</A>. There are four ways to tell BackupPC the
896     smb share password:</p>
897     </dd>
898     <ul>
899     <li>
900     As an environment variable BPC_SMB_PASSWD set before BackupPC starts.
901     If you start BackupPC manually the BPC_SMB_PASSWD variable must be set
902     manually first. For backward compatibility for v1.5.0 and prior, the
903     environment variable PASSWD can be used if BPC_SMB_PASSWD is not set.
904     Warning: on some systems it is possible to see environment variables of
905     running processes.
906     <p></p>
907     <li>
908     Alternatively the BPC_SMB_PASSWD setting can be included in
909     /etc/init.d/backuppc, in which case you must make sure this file
910     is not world (other) readable.
911     <p></p>
912     <li>
913     As a configuration variable <a href="#item_%24conf%7bsmbsharepasswd%7d">$Conf{SmbSharePasswd}</A> in
914     __TOPDIR__/conf/config.pl. If you put the password
915     here you must make sure this file is not world (other) readable.
916     <p></p>
917     <li>
918     As a configuration variable <a href="#item_%24conf%7bsmbsharepasswd%7d">$Conf{SmbSharePasswd}</A> in the per-PC
919     configuration file, __TOPDIR__/pc/$host/config.pl. You will have to
920     use this option if the smb share password is different for each host.
921     If you put the password here you must make sure this file is not
922     world (other) readable.
923     <p></p></ul>
924     <p>Placement and protection of the smb share password is a possible
925     security risk, so please double-check the file and directory
926     permissions. In a future version there might be support for
927     encryption of this password, but a private key will still have to
928     be stored in a protected place. Suggestions are welcome.</p>
929     <p>As an alternative to setting <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> to ``smb'' (using
930     smbclient) for WinXX clients, you can use an smb network filesystem (eg:
931     ksmbfs or similar) on your linux/unix server to mount the share,
932     and then set <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> to ``tar'' (use tar on the network
933     mounted file system).</p>
934     <p>Also, to make sure that file names with 8-bit characters are correctly
935     transferred by smbclient you should add this to samba's smb.conf file
936     for samba 2.x:</p>
937     <pre>
938     [global]
939     # Accept the windows charset
940     client code page = 850
941     character set = ISO8859-1</pre>
942     <p>For samba 3.x this should instead be:</p>
943     <pre>
944     [global]
945     unix charset = ISO8859-1</pre>
946     <p>This setting should work for western europe.
947     See <a href="http://www.oreilly.com/catalog/samba/chapter/book/ch08_03.html">http://www.oreilly.com/catalog/samba/chapter/book/ch08_03.html</a>
948     for more information about settings for other languages.</p>
949     <dt><strong><a name="item_linux_2funix">Linux/Unix</a></strong><br />
950     </dt>
951     <dd>
952     The preferred setup for linux/unix clients is to set <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A>
953     to ``rsync'', ``rsyncd'' or ``tar''.
954     </dd>
955     <dd>
956     <p>You can use either rsync, smb, or tar for linux/unix machines. Smb requires
957     that the Samba server (smbd) be run to provide the shares. Since the smb
958     protocol can't represent special files like symbolic links and fifos,
959     tar and rsync are the better transport methods for linux/unix machines.
960     (In fact, by default samba makes symbolic links look like the file or
961     directory that they point to, so you could get an infinite loop if a
962     symbolic link points to the current or parent directory. If you really
963     need to use Samba shares for linux/unix backups you should turn off the
964     ``follow symlinks'' samba config setting. See the smb.conf manual page.)</p>
965     </dd>
966     <dd>
967     <p>The requirements for each Xfer Method are:</p>
968     </dd>
969     <dl>
970     <dt><strong><a name="item_tar">tar</a></strong><br />
971     </dt>
972     <dd>
973     You must have GNU tar on the client machine. Use ``tar --version''
974     or ``gtar --version'' to verify. The version should be at least
975     1.13.7, and 1.13.20 or greater is recommended. Tar is run on
976     the client machine via rsh or ssh.
977     </dd>
978     <dd>
979     <p>The relevant configuration settings are <a href="#item_%24conf%7btarclientpath%7d">$Conf{TarClientPath}</A>,
980     <a href="#item_%24conf%7btarsharename%7d">$Conf{TarShareName}</A>, <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A>, <a href="#item_%24conf%7btarfullargs%7d">$Conf{TarFullArgs}</A>,
981     <a href="#item_%24conf%7btarincrargs%7d">$Conf{TarIncrArgs}</A>, and <a href="#item_%24conf%7btarclientrestorecmd%7d">$Conf{TarClientRestoreCmd}</A>.</p>
982     </dd>
983     <p></p>
984     <dt><strong><a name="item_rsync">rsync</a></strong><br />
985     </dt>
986     <dd>
987     You should have at least rsync 2.5.5, and the latest version 2.5.6
988     is recommended. Rsync is run on the remote client via rsh or ssh.
989     </dd>
990     <dd>
991     <p>The relevant configuration settings are <a href="#item_%24conf%7brsyncclientpath%7d">$Conf{RsyncClientPath}</A>,
992     <a href="#item_%24conf%7brsyncclientcmd%7d">$Conf{RsyncClientCmd}</A>, <a href="#item_%24conf%7brsyncclientrestorecmd%7d">$Conf{RsyncClientRestoreCmd}</A>, <a href="#item_%24conf%7brsyncsharename%7d">$Conf{RsyncShareName}</A>,
993     <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A>, and <a href="#item_%24conf%7brsyncrestoreargs%7d">$Conf{RsyncRestoreArgs}</A>.</p>
994     </dd>
995     <p></p>
996     <dt><strong><a name="item_rsyncd">rsyncd</a></strong><br />
997     </dt>
998     <dd>
999     You should have at least rsync 2.5.5, and the latest version 2.6.2
1000     is recommended. In this case the rsync daemon should be running on
1001     the client machine and BackupPC connects directly to it.
1002     </dd>
1003     <dd>
1004     <p>The relevant configuration settings are <a href="#item_%24conf%7brsyncdclientport%7d">$Conf{RsyncdClientPort}</A>,
1005     <a href="#item_%24conf%7brsyncdusername%7d">$Conf{RsyncdUserName}</A>, <a href="#item_%24conf%7brsyncdpasswd%7d">$Conf{RsyncdPasswd}</A>, <a href="#item_%24conf%7brsyncdauthrequired%7d">$Conf{RsyncdAuthRequired}</A>,
1006     <a href="#item_%24conf%7brsyncsharename%7d">$Conf{RsyncShareName}</A>, <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A>, and <a href="#item_%24conf%7brsyncrestoreargs%7d">$Conf{RsyncRestoreArgs}</A>.
1007     <a href="#item_%24conf%7brsyncsharename%7d">$Conf{RsyncShareName}</A> is the name of an rsync module (ie: the thing
1008     in square brackets in rsyncd's conf file -- see rsyncd.conf), not a
1009     file system path.</p>
1010     </dd>
1011     <dd>
1012     <p>Be aware that rsyncd will remove the leading '/' from path names in
1013     symbolic links if you specify ``use chroot = no'' in the rsynd.conf file.
1014     See the rsyncd.conf manual page for more information.</p>
1015     </dd>
1016     <p></p></dl>
1017     <p>For linux/unix machines you should not backup ``/proc''. This directory
1018     contains a variety of files that look like regular files but they are
1019     special files that don't need to be backed up (eg: /proc/kcore is a
1020     regular file that contains physical memory). See <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A>.
1021     It is safe to back up /dev since it contains mostly character-special
1022     and block-special files, which are correctly handed by BackupPC
1023     (eg: backing up /dev/hda5 just saves the block-special file information,
1024     not the contents of the disk).</p>
1025     <p>Alternatively, rather than backup all the file systems as a single
1026     share (``/''), it is easier to restore a single file system if you backup
1027     each file system separately. To do this you should list each file system
1028     mount point in <a href="#item_%24conf%7btarsharename%7d">$Conf{TarShareName}</A> or <a href="#item_%24conf%7brsyncsharename%7d">$Conf{RsyncShareName}</A>, and add the
1029     --one-file-system option to <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A> or add --one-file-system
1030     (note the different punctuation) to <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A>. In this case there
1031     is no need to exclude /proc explicitly since it looks like a different
1032     file system.</p>
1033     <p>Next you should decide whether to run tar over ssh, rsh or nfs. Ssh is
1034     the preferred method. Rsh is not secure and therefore not recommended.
1035     Nfs will work, but you need to make sure that the BackupPC user (running
1036     on the server) has sufficient permissions to read all the files below
1037     the nfs mount.</p>
1038     <p>Ssh allows BackupPC to run as a privileged user on the client (eg:
1039     root), since it needs sufficient permissions to read all the backup
1040     files. Ssh is setup so that BackupPC on the server (an otherwise low
1041     privileged user) can ssh as root on the client, without being prompted
1042     for a password. There are two common versions of ssh: v1 and v2. Here
1043     are some instructions for one way to setup ssh. (Check which version
1044     of SSH you have by typing ``ssh'' or ``man ssh''.)</p>
1045     <dt><strong><a name="item_mac_os_x">Mac OS X</a></strong><br />
1046     </dt>
1047     <dd>
1048     In general this should be similar to Linux/Unix machines.
1049     Mark Stosberg reports that you can also use hfstar.
1050     See <a href="http://fink.sourceforge.net/pdb/package.php/hfstar">http://fink.sourceforge.net/pdb/package.php/hfstar</a>.
1051     </dd>
1052     <p></p>
1053     <dt><strong><a name="item_ssh_setup">SSH Setup</a></strong><br />
1054     </dt>
1055     <dd>
1056     SSH is a secure way to run tar or rsync on a backup client to extract
1057     the data. SSH provides strong authentication and encryption of
1058     the network data.
1059     </dd>
1060     <dd>
1061     <p>Note that if you run rsyncd (rsync daemon), ssh is not used.
1062     In this case, rsyncd provides its own authentication, but there
1063     is no encryption of network data. If you want encryption of
1064     network data you can use ssh to create a tunnel, or use a
1065     program like stunnel. If someone submits instructions I</p>
1066     </dd>
1067     <dd>
1068     <p>Setup instructions for ssh are at
1069     <a href="http://backuppc.sourceforge.net/faq/ssh.html">http://backuppc.sourceforge.net/faq/ssh.html</a>.</p>
1070     </dd>
1071     <p></p>
1072     <dt><strong><a name="item_clients_that_use_dhcp">Clients that use DHCP</a></strong><br />
1073     </dt>
1074     <dd>
1075     If a client machine uses DHCP BackupPC needs some way to find the
1076     IP address given the host name. One alternative is to set dhcp
1077     to 1 in the hosts file, and BackupPC will search a pool of IP
1078     addresses looking for hosts. More efficiently, it is better to
1079     set dhcp = 0 and provide a mechanism for BackupPC to find the
1080     IP address given the host name.
1081     </dd>
1082     <dd>
1083     <p>For WinXX machines BackupPC uses the NetBios name server to determine
1084     the IP address given the host name.
1085     For unix machines you can run nmbd (the NetBios name server) from
1086     the Samba distribution so that the machine responds to a NetBios
1087     name request. See the manual page and Samba documentation for more
1088     information.</p>
1089     </dd>
1090     <dd>
1091     <p>Alternatively, you can set <a href="#item_%24conf%7bnmblookupfindhostcmd%7d">$Conf{NmbLookupFindHostCmd}</A> to any command
1092     that returns the IP address given the host name.</p>
1093     </dd>
1094     <dd>
1095     <p>Please read the section <a href="#how_backuppc_finds_hosts">How BackupPC Finds Hosts</a>
1096     for more details.</p>
1097     </dd>
1098     <p></p></dl>
1099     <p>
1100     </p>
1101     <h2><a name="step_6__running_backuppc">Step 6: Running BackupPC</a></h2>
1102     <p>The installation contains an init.d backuppc script that can be copied
1103     to /etc/init.d so that BackupPC can auto-start on boot.
1104     See init.d/README for further instructions.</p>
1105     <p>BackupPC should be ready to start. If you installed the init.d script,
1106     then you should be able to run BackupPC with:</p>
1107     <pre>
1108     /etc/init.d/backuppc start</pre>
1109     <p>(This script can also be invoked with ``stop'' to stop BackupPC and ``reload''
1110     to tell BackupPC to reload config.pl and the hosts file.)</p>
1111     <p>Otherwise, just run</p>
1112     <pre>
1113     __INSTALLDIR__/bin/BackupPC -d</pre>
1114     <p>as user __BACKUPPCUSER__. The -d option tells BackupPC to run as a daemon
1115     (ie: it does an additional fork).</p>
1116     <p>Any immediate errors will be printed to stderr and BackupPC will quit.
1117     Otherwise, look in __TOPDIR__/log/LOG and verify that BackupPC reports
1118     it has started and all is ok.</p>
1119     <p>
1120     </p>
1121     <h2><a name="step_7__talking_to_backuppc">Step 7: Talking to BackupPC</a></h2>
1122     <p>Note: as of version 1.5.0, BackupPC no longer supports telnet
1123     to its TCP port. First off, a unix domain socket is used
1124     instead of a TCP port. (The TCP port can still be re-enabled
1125     if your installation has apache and BackupPC running on different
1126     machines.) Secondly, even if you still use the TCP port, the
1127     messages exchanged over this interface are now protected by
1128     an MD5 digest based on a shared secret (see <a href="#item_%24conf%7bservermesgsecret%7d">$Conf{ServerMesgSecret}</A>)
1129     as well as sequence numbers and per-session unique keys, preventing
1130     forgery and replay attacks.</p>
1131     <p>You should verify that BackupPC is running by using BackupPC_serverMesg.
1132     This sends a message to BackupPC via the unix (or TCP) socket and prints
1133     the response.</p>
1134     <p>You can request status information and start and stop backups using this
1135     interface. This socket interface is mainly provided for the CGI interface
1136     (and some of the BackupPC sub-programs use it too). But right now we just
1137     want to make sure BackupPC is happy. Each of these commands should
1138     produce some status output:</p>
1139     <pre>
1140     __INSTALLDIR__/bin/BackupPC_serverMesg status info
1141     __INSTALLDIR__/bin/BackupPC_serverMesg status jobs
1142     __INSTALLDIR__/bin/BackupPC_serverMesg status hosts</pre>
1143     <p>The output should be some hashes printed with Data::Dumper. If it
1144     looks cryptic and confusing, and doesn't look like an error message,
1145     then all is ok.</p>
1146     <p>The jobs status should initially show just BackupPC_trashClean.
1147     The hosts status should produce a list of every host you have listed
1148     in __TOPDIR__/conf/hosts as part of a big cryptic output line.</p>
1149     <p>You can also request that all hosts be queued:</p>
1150     <pre>
1151     __INSTALLDIR__/bin/BackupPC_serverMesg backup all</pre>
1152     <p>At this point you should make sure the CGI interface works since
1153     it will be much easier to see what is going on. That's our
1154     next subject.</p>
1155     <p>
1156     </p>
1157     <h2><a name="step_8__cgi_interface">Step 8: CGI interface</a></h2>
1158     <p>The CGI interface script, BackupPC_Admin, is a powerful and flexible
1159     way to see and control what BackupPC is doing. It is written for an
1160     Apache server. If you don't have Apache, see <a href="http://www.apache.org">http://www.apache.org</a>.</p>
1161     <p>There are two options for setting up the CGI interface: standard
1162     mode and using mod_perl. Mod_perl provides much higher performance
1163     (around 15x) and is the best choice if your Apache was built with
1164     mod_perl support. To see if your apache was built with mod_perl
1165     run this command:</p>
1166     <pre>
1167     httpd -l | egrep mod_perl</pre>
1168     <p>If this prints mod_perl.c then your Apache supports mod_perl.</p>
1169     <p>Using mod_perl with BackupPC_Admin requires a dedicated Apache
1170     to be run as the BackupPC user (__BACKUPPCUSER__). This is
1171     because BackupPC_Admin needs permission to access various files
1172     in BackupPC's data directories. In contrast, the standard
1173     installation (without mod_perl) solves this problem by having
1174     BackupPC_Admin installed as setuid to the BackupPC user, so that
1175     BackupPC_Admin runs as the BackuPC user.</p>
1176     <p>Here are some specifics for each setup:</p>
1177     <dl>
1178     <dt><strong><a name="item_standard_setup">Standard Setup</a></strong><br />
1179     </dt>
1180     <dd>
1181     The CGI interface should have been installed by the configure.pl script
1182     in __CGIDIR__/BackupPC_Admin. BackupPC_Admin should have been installed
1183     as setuid to the BackupPC user (__BACKUPPCUSER__), in addition to user
1184     and group execute permission.
1185     </dd>
1186     <dd>
1187     <p>You should be very careful about permissions on BackupPC_Admin and
1188     the directory __CGIDIR__: it is important that normal users cannot
1189     directly execute or change BackupPC_Admin, otherwise they can access
1190     backup files for any PC. You might need to change the group ownership
1191     of BackupPC_Admin to a group that Apache belongs to so that Apache
1192     can execute it (don't add ``other'' execute permission!).
1193     The permissions should look like this:</p>
1194     </dd>
1195     <dd>
1196     <pre>
1197     ls -l __CGIDIR__/BackupPC_Admin
1198     -swxr-x--- 1 __BACKUPPCUSER__ web 82406 Jun 17 22:58 __CGIDIR__/BackupPC_Admin</pre>
1199     </dd>
1200     <dd>
1201     <p>The setuid script won't work unless perl on your machine was installed
1202     with setuid emulation. This is likely the problem if you get an error
1203     saying such as ``Wrong user: my userid is 25, instead of 150'', meaning
1204     the script is running as the httpd user, not the BackupPC user.
1205     This is because setuid scripts are disabled by the kernel in most
1206     flavors of unix and linux.</p>
1207     </dd>
1208     <dd>
1209     <p>To see if your perl has setuid emulation, see if there is a program
1210     called sperl5.6.0 (or sperl5.8.2 etc, based on your perl version)
1211     in the place where perl is installed. If you can't find this program,
1212     then you have two options: rebuild and reinstall perl with the setuid
1213     emulation turned on (answer ``y'' to the question ``Do you want to do
1214     setuid/setgid emulation?'' when you run perl's configure script), or
1215     switch to the mod_perl alternative for the CGI script (which doesn't
1216     need setuid to work).</p>
1217     </dd>
1218     <p></p>
1219     <dt><strong><a name="item_mod_perl_setup">Mod_perl Setup</a></strong><br />
1220     </dt>
1221     <dd>
1222     The advantage of the mod_perl setup is that no setuid script is needed,
1223     and there is a huge performance advantage. Not only does all the perl
1224     code need to be parsed just once, the config.pl and hosts files, plus
1225     the connection to the BackupPC server are cached between requests. The
1226     typical speedup is around 15 times.
1227     </dd>
1228     <dd>
1229     <p>To use mod_perl you need to run Apache as user __BACKUPPCUSER__.
1230     If you need to run multiple Apache's for different services then
1231     you need to create multiple top-level Apache directories, each
1232     with their own config file. You can make copies of /etc/init.d/httpd
1233     and use the -d option to httpd to point each http to a different
1234     top-level directory. Or you can use the -f option to explicitly
1235     point to the config file. Multiple Apache's will run on different
1236     Ports (eg: 80 is standard, 8080 is a typical alternative port accessed
1237     via <a href="http://yourhost.com:8080).">http://yourhost.com:8080).</a></p>
1238     </dd>
1239     <dd>
1240     <p>Inside BackupPC's Apache http.conf file you should check the
1241     settings for ServerRoot, DocumentRoot, User, Group, and Port. See
1242     <a href="http://httpd.apache.org/docs/server-wide.html">http://httpd.apache.org/docs/server-wide.html</a> for more details.</p>
1243     </dd>
1244     <dd>
1245     <p>For mod_perl, BackupPC_Admin should not have setuid permission, so
1246     you should turn it off:</p>
1247     </dd>
1248     <dd>
1249     <pre>
1250     chmod u-s __CGIDIR__/BackupPC_Admin</pre>
1251     </dd>
1252     <dd>
1253     <p>To tell Apache to use mod_perl to execute BackupPC_Admin, add this
1254     to Apache's 1.x httpd.conf file:</p>
1255     </dd>
1256     <dd>
1257     <pre>
1258     &lt;IfModule mod_perl.c&gt;
1259     PerlModule Apache::Registry
1260     PerlTaintCheck On
1261     &lt;Location /cgi-bin/BackupPC/BackupPC_Admin&gt; # &lt;--- change path as needed
1262     SetHandler perl-script
1263     PerlHandler Apache::Registry
1264     Options ExecCGI
1265     PerlSendHeader On
1266     &lt;/Location&gt;
1267     &lt;/IfModule&gt;</pre>
1268     </dd>
1269     <dd>
1270     <p>Apache 2.0.44 with Perl 5.8.0 on RedHat 7.1, Don Silvia reports that
1271     this works (with tweaks from Michael Tuzi):</p>
1272     </dd>
1273     <dd>
1274     <pre>
1275     LoadModule perl_module modules/mod_perl.so
1276     PerlModule Apache2</pre>
1277     </dd>
1278     <dd>
1279     <pre>
1280     &lt;Directory /path/to/cgi/&gt;
1281     SetHandler perl-script
1282     PerlResponseHandler ModPerl::Registry
1283     PerlOptions +ParseHeaders
1284     Options +ExecCGI
1285     Order deny,allow
1286     Deny from all
1287     Allow from 192.168.0
1288     AuthName &quot;Backup Admin&quot;
1289     AuthType Basic
1290     AuthUserFile /path/to/user_file
1291     Require valid-user
1292     &lt;/Directory&gt;</pre>
1293     </dd>
1294     <dd>
1295     <p>There are other optimizations and options with mod_perl. For
1296     example, you can tell mod_perl to preload various perl modules,
1297     which saves memory compared to loading separate copies in every
1298     Apache process after they are forked. See Stas's definitive
1299     mod_perl guide at <a href="http://perl.apache.org/guide">http://perl.apache.org/guide</a>.</p>
1300     </dd>
1301     <p></p></dl>
1302     <p>BackupPC_Admin requires that users are authenticated by Apache.
1303     Specifically, it expects that Apache sets the REMOTE_USER environment
1304     variable when it runs. There are several ways to do this. One way
1305     is to create a .htaccess file in the cgi-bin directory that looks like:</p>
1306     <pre>
1307     AuthGroupFile /etc/httpd/conf/group # &lt;--- change path as needed
1308     AuthUserFile /etc/http/conf/passwd # &lt;--- change path as needed
1309     AuthType basic
1310     AuthName &quot;access&quot;
1311     require valid-user</pre>
1312     <p>You will also need ``AllowOverride Indexes AuthConfig'' in the Apache
1313     httpd.conf file to enable the .htaccess file. Alternatively, everything
1314     can go in the Apache httpd.conf file inside a Location directive. The
1315     list of users and password file above can be extracted from the NIS
1316     passwd file.</p>
1317     <p>One alternative is to use LDAP. In Apache's http.conf add these lines:</p>
1318     <pre>
1319     LoadModule auth_ldap_module modules/auth_ldap.so
1320     AddModule auth_ldap.c</pre>
1321     <pre>
1322     # cgi-bin - auth via LDAP (for BackupPC)
1323     &lt;Location /cgi-binBackupPC/BackupPC_Admin&gt; # &lt;--- change path as needed
1324     AuthType Basic
1325     AuthName &quot;BackupPC login&quot;
1326     # replace MYDOMAIN, PORT, ORG and CO as needed
1327     AuthLDAPURL ldap://ldap.MYDOMAIN.com:PORT/o=ORG,c=CO?uid?sub?(objectClass=*)
1328     require valid-user
1329     &lt;/Location&gt;</pre>
1330     <p>If you want to disable the user authentication you can set
1331     <a href="#item_%24conf%7bcgiadminusers%7d">$Conf{CgiAdminUsers}</A> to '*', which allows any user to have
1332     full access to all hosts and backups. In this case the REMOTE_USER
1333     environment variable does not have to be set by Apache.</p>
1334     <p>Alternatively, you can force a particular user name by getting Apache
1335     to set REMOTE_USER, eg, to hardcode the user to www you could add
1336     this to Apache's httpd.conf:</p>
1337     <pre>
1338     &lt;Location /cgi-bin/BackupPC/BackupPC_Admin&gt; # &lt;--- change path as needed
1339     Setenv REMOTE_USER www
1340     &lt;/Location&gt;</pre>
1341     <p>Finally, you should also edit the config.pl file and adjust, as necessary,
1342     the CGI-specific settings. They're near the end of the config file. In
1343     particular, you should specify which users or groups have administrator
1344     (privileged) access: see the config settings <a href="#item_%24conf%7bcgiadminusergroup%7d">$Conf{CgiAdminUserGroup}</A>
1345     and <a href="#item_%24conf%7bcgiadminusers%7d">$Conf{CgiAdminUsers}</A>. Also, the configure.pl script placed various
1346     images into <a href="#item_%24conf%7bcgiimagedir%7d">$Conf{CgiImageDir}</A> that BackupPC_Admin needs to serve
1347     up. You should make sure that <a href="#item_%24conf%7bcgiimagedirurl%7d">$Conf{CgiImageDirURL}</A> is the correct
1348     URL for the image directory.</p>
1349     <p>See the section <a href="#fixing_installation_problems">Fixing installation problems</a> for suggestions on debugging the Apache authentication setup.</p>
1350     <p>
1351     </p>
1352     <h2><a name="how_backuppc_finds_hosts">How BackupPC Finds Hosts</a></h2>
1353     <p>Starting with v2.0.0 the way hosts are discovered has changed. In most
1354     cases you should specify 0 for the DHCP flag in the conf/hosts file,
1355     even if the host has a dynamically assigned IP address.</p>
1356     <p>BackupPC (starting with v2.0.0) looks up hosts with DHCP = 0 in this manner:</p>
1357     <ul>
1358     <li>
1359     First DNS is used to lookup the IP address given the client's name
1360     using perl's <code>gethostbyname()</code> function. This should succeed for machines
1361     that have fixed IP addresses that are known via DNS. You can manually
1362     see whether a given host have a DNS entry according to perls'
1363     gethostbyname function with this command:
1364     <pre>
1365     perl -e 'print(gethostbyname(&quot;myhost&quot;) ? &quot;ok\n&quot; : &quot;not found\n&quot;);'</pre>
1366     <p></p>
1367     <li>
1368     If <code>gethostbyname()</code> fails, BackupPC then attempts a NetBios multicast to
1369     find the host. Provided your client machine is configured properly,
1370     it should respond to this NetBios multicast request. Specifically,
1371     BackupPC runs a command of this form:
1372     <pre>
1373     nmblookup myhost</pre>
1374     <p>If this fails you will see output like:</p>
1375     <pre>
1376     querying myhost on 10.10.255.255
1377     name_query failed to find name myhost</pre>
1378     <p>If this success you will see output like:</p>
1379     <pre>
1380     querying myhost on 10.10.255.255
1381     10.10.1.73 myhost&lt;00&gt;</pre>
1382     <p>Depending on your netmask you might need to specify the -B option to
1383     nmblookup. For example:</p>
1384     <pre>
1385     nmblookup -B 10.10.1.255 myhost</pre>
1386     <p>If necessary, experiment on the nmblookup command that will return the
1387     IP address of the client given its name. Then update
1388     <a href="#item_%24conf%7bnmblookupfindhostcmd%7d">$Conf{NmbLookupFindHostCmd}</A> with any necessary options to nmblookup.</p>
1389     <p></p></ul>
1390     <p>For hosts that have the DHCP flag set to 1, these machines are
1391     discovered as follows:</p>
1392     <ul>
1393     <li>
1394     A DHCP address pool (<a href="#item_%24conf%7bdhcpaddressranges%7d">$Conf{DHCPAddressRanges}</A>) needs to be specified.
1395     BackupPC will check the NetBIOS name of each machine in the range using
1396     a command of the form:
1397     <pre>
1398     nmblookup -A W.X.Y.Z</pre>
1399     <p>where W.X.Y.Z is each candidate address from <a href="#item_%24conf%7bdhcpaddressranges%7d">$Conf{DHCPAddressRanges}</A>.
1400     Any host that has a valid NetBIOS name returned by this command (ie:
1401     matching an entry in the hosts file) will be backed up. You can
1402     modify the specific nmblookup command if necessary via <a href="#item_%24conf%7bnmblookupcmd%7d">$Conf{NmbLookupCmd}</A>.</p>
1403     <p></p>
1404     <li>
1405     You only need to use this DHCP feature if your client machine doesn't
1406     respond to the NetBios multicast request:
1407     <pre>
1408     nmblookup myHost</pre>
1409     <p>but does respond to a request directed to its IP address:</p>
1410     <pre>
1411     nmblookup -A W.X.Y.Z</pre>
1412     <p></p></ul>
1413     <p>
1414     </p>
1415     <h2><a name="other_installation_topics">Other installation topics</a></h2>
1416     <dl>
1417     <dt><strong><a name="item_removing_a_client">Removing a client</a></strong><br />
1418     </dt>
1419     <dd>
1420     If there is a machine that no longer needs to be backed up (eg: a retired
1421     machine) you have two choices. First, you can keep the backups accessible
1422     and browsable, but disable all new backups. Alternatively, you can
1423     completely remove the client and all its backups.
1424     </dd>
1425     <dd>
1426     <p>To disable backups for a client there are two special values for
1427     <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A> in that client's per-PC config.pl file:</p>
1428     </dd>
1429     <dl>
1430     <dt><strong><a name="item__2d1">-1</a></strong><br />
1431     </dt>
1432     <dd>
1433     Don't do any regular backups on this machine. Manually
1434     requested backups (via the CGI interface) will still occur.
1435     </dd>
1436     <p></p>
1437     <dt><strong><a name="item__2d2">-2</a></strong><br />
1438     </dt>
1439     <dd>
1440     Don't do any backups on this machine. Manually requested
1441     backups (via the CGI interface) will be ignored.
1442     </dd>
1443     <p></p></dl>
1444     <p>This will still allow that client's old backups to be browsable
1445     and restorable.</p>
1446     <p>To completely remove a client and all its backups, you should remove its
1447     entry in the conf/hosts file, and then delete the __TOPDIR__/pc/$host
1448     directory. Whenever you change the hosts file, you should send
1449     BackupPC a HUP (-1) signal so that it re-reads the hosts file.
1450     If you don't do this, BackupPC will automatically re-read the
1451     hosts file at the next regular wakeup.</p>
1452     <p>Note that when you remove a client's backups you won't initially recover
1453     a lot of disk space. That's because the client's files are still in
1454     the pool. Overnight, when BackupPC_nightly next runs, all the unused
1455     pool files will be deleted and this will recover the disk space used
1456     by the client's backups.</p>
1457     <dt><strong><a name="item_copying_the_pool">Copying the pool</a></strong><br />
1458     </dt>
1459     <dd>
1460     If the pool disk requirements grow you might need to copy the entire
1461     data directory to a new (bigger) file system. Hopefully you are lucky
1462     enough to avoid this by having the data directory on a RAID file system
1463     or LVM that allows the capacity to be grown in place by adding disks.
1464     </dd>
1465     <dd>
1466     <p>The backup data directories contain large numbers of hardlinks. If
1467     you try to copy the pool the target directory will occupy a lot more
1468     space if the hardlinks aren't re-established.</p>
1469     </dd>
1470     <dd>
1471     <p>The GNU cp program with the -a option is aware of hardlinks and knows
1472     to re-establish them. So GNU cp -a is the recommended way to copy
1473     the data directory and pool. Don't forget to stop BackupPC while
1474     the copy runs.</p>
1475     </dd>
1476     <p></p>
1477     <dt><strong><a name="item_compressing_an_existing_pool">Compressing an existing pool</a></strong><br />
1478     </dt>
1479     <dd>
1480     If you are upgrading BackupPC and want to turn compression on you have
1481     two choices:
1482     </dd>
1483     <ul>
1484     <li>
1485     Simply turn on compression. All new backups will be compressed. Both old
1486     (uncompressed) and new (compressed) backups can be browsed and viewed.
1487     Eventually, the old backups will expire and all the pool data will be
1488     compressed. However, until the old backups expire, this approach could
1489     require 60% or more additional pool storage space to store both
1490     uncompressed and compressed versions of the backup files.
1491     <p></p>
1492     <li>
1493     Convert all the uncompressed pool files and backups to compressed.
1494     The script __INSTALLDIR__/bin/BackupPC_compressPool does this.
1495     BackupPC must not be running when you run BackupPC_compressPool.
1496     Also, there must be no existing compressed backups when you
1497     run BackupPC_compressPool.
1498     <p>BackupPC_compressPool compresses all the files in the uncompressed pool
1499     (__TOPDIR__/pool) and moves them to the compressed pool
1500     (__TOPDIR__/cpool). It rewrites the files in place, so that the
1501     existing hardlinks are not disturbed.</p>
1502     <p></p></ul>
1503     <p>The rest of this section discusses how to run BackupPC_compressPool.</p>
1504     <p>BackupPC_compressPool takes three command line options:</p>
1505     <dl>
1506     <dt><strong><a name="item__2dt">-t</a></strong><br />
1507     </dt>
1508     <dd>
1509     Test mode: do everything except actually replace the pool files.
1510     Useful for estimating total run time without making any real
1511     changes.
1512     </dd>
1513     <p></p>
1514     <dt><strong><a name="item__2dr">-r</a></strong><br />
1515     </dt>
1516     <dd>
1517     Read check: re-read the compressed file and compare it against
1518     the original uncompressed file. Can only be used in test mode.
1519     </dd>
1520     <p></p>
1521     <dt><strong><a name="item__2dc__23">-c #</a></strong><br />
1522     </dt>
1523     <dd>
1524     Number of children to fork. BackupPC_compressPool can take a long time
1525     to run, so to speed things up it spawns four children, each working on a
1526     different part of the pool. You can change the number of children with
1527     the -c option.
1528     </dd>
1529     <p></p></dl>
1530     <p>Here are the recommended steps for running BackupPC_compressPool:</p>
1531     <ul>
1532     <li>
1533     Stop BackupPC (eg: ``/etc/init.d/backuppc stop'').
1534     <p></p>
1535     <li>
1536     Set <a href="#item_%24conf%7bcompresslevel%7d">$Conf{CompressLevel}</A> to a non-zero number (eg: 3).
1537     <p></p>
1538     <li>
1539     Do a dry run of BackupPC_compressPool. Make sure you run this as
1540     the BackupPC user (__BACKUPPCUSER__):
1541     <pre>
1542     BackupPC_compressPool -t -r</pre>
1543     <p>The -t option (test mode) makes BackupPC_compressPool do all the steps,
1544     but not actually change anything. The -r option re-reads the compressed
1545     file and compares it against the original.</p>
1546     <p>BackupPC_compressPool gives a status as it completes each 1% of the job.
1547     It also shows the cumulative compression ratio and estimated completion
1548     time. Once you are comfortable that things look ok, you can kill
1549     BackupPC_compressPool or wait for it to finish.</p>
1550     <p></p>
1551     <li>
1552     Now you are ready to run BackupPC_compressPool for real. Once again,
1553     as the BackupPC user (__BACKUPPCUSER__), run:
1554     <pre>
1555     BackupPC_compressPool</pre>
1556     <p>You should put the output into a file and tail this file. (The running
1557     time could be twice as long as the test mode since the test mode file
1558     writes are immediately followed by an unlink, so in test mode it is
1559     likely the file writes never make it to disk.)</p>
1560     <p>It is <strong>critical</strong> that BackupPC_compressPool runs to completion before
1561     re-starting BackupPC. Before BackupPC_compressPool completes, none of
1562     the existing backups will be in a consistent state. If you must stop
1563     BackupPC_compressPool for some reason, send it an INT or TERM signal
1564     and give it several seconds (or more) to clean up gracefully.
1565     After that, you can re-run BackupPC_compressPool and it will start
1566     again where it left off. Once again, it is critical that it runs
1567     to 100% completion.</p>
1568     <p></p></ul>
1569     <p>After BackupPC_compressPool completes you should have a complete set
1570     of compressed backups (and your disk usage should be lower). You
1571     can now re-start BackupPC.</p>
1572     </dl>
1573     <p>
1574     </p>
1575     <h2><a name="fixing_installation_problems">Fixing installation problems</a></h2>
1576     <p>Please see the FAQ at <a href="http://backuppc.sourceforge.net/faq">http://backuppc.sourceforge.net/faq</a> for
1577     debugging suggestions.</p>
1578     <p>
1579     <a href="#__index__"><small>Back to Top</small></a>
1580     </p>
1581     <hr />
1582     <h1><a name="restore_functions">Restore functions</a></h1>
1583     <p>BackupPC supports several different methods for restoring files. The
1584     most convenient restore options are provided via the CGI interface.
1585     Alternatively, backup files can be restored using manual commands.</p>
1586     <p>
1587     </p>
1588     <h2><a name="cgi_restore_options">CGI restore options</a></h2>
1589     <p>By selecting a host in the CGI interface, a list of all the backups
1590     for that machine will be displayed. By selecting the backup number
1591     you can navigate the shares and directory tree for that backup.</p>
1592     <p>BackupPC's CGI interface automatically fills incremental backups
1593     with the corresponding full backup, which means each backup has
1594     a filled appearance. Therefore, there is no need to do multiple
1595     restores from the incremental and full backups: BackupPC does all
1596     the hard work for you. You simply select the files and directories
1597     you want from the correct backup vintage in one step.</p>
1598     <p>You can download a single backup file at any time simply by selecting
1599     it. Your browser should prompt you with the file name and ask you
1600     whether to open the file or save it to disk.</p>
1601     <p>Alternatively, you can select one or more files or directories in
1602     the currently selected directory and select ``Restore selected files''.
1603     (If you need to restore selected files and directories from several
1604     different parent directories you will need to do that in multiple
1605     steps.)</p>
1606     <p>If you select all the files in a directory, BackupPC will replace
1607     the list of files with the parent directory. You will be presented
1608     with a screen that has three options:</p>
1609     <dl>
1610     <dt><strong><a name="item_option_1_3a_direct_restore">Option 1: Direct Restore</a></strong><br />
1611     </dt>
1612     <dd>
1613     With this option the selected files and directories are restored
1614     directly back onto the host, by default in their original location.
1615     Any old files with the same name will be overwritten, so use caution.
1616     You can optionally change the target host name, target share name,
1617     and target path prefix for the restore, allowing you to restore the
1618     files to a different location.
1619     </dd>
1620     <dd>
1621     <p>Once you select ``Start Restore'' you will be prompted one last time
1622     with a summary of the exact source and target files and directories
1623     before you commit. When you give the final go ahead the restore
1624     operation will be queued like a normal backup job, meaning that it
1625     will be deferred if there is a backup currently running for that host.
1626     When the restore job is run, smbclient, tar, rsync or rsyncd is used
1627     (depending upon <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A>) to actually restore the files.
1628     Sorry, there is currently no option to cancel a restore that has been
1629     started.</p>
1630     </dd>
1631     <dd>
1632     <p>A record of the restore request, including the result and list of
1633     files and directories, is kept. It can be browsed from the host's
1634     home page. <a href="#item_%24conf%7brestoreinfokeepcnt%7d">$Conf{RestoreInfoKeepCnt}</A> specifies how many old restore
1635     status files to keep.</p>
1636     </dd>
1637     <dd>
1638     <p>Note that for direct restore to work, the <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> must
1639     be able to write to the client. For example, that means an SMB
1640     share for smbclient needs to be writable, and the rsyncd module
1641     needs ``read only'' set to ``yes''. This creates additional security
1642     risks. If you only create read-only SMB shares (which is a good
1643     idea), then the direct restore will fail. You can disable the
1644     direct restore option by setting <a href="#item_%24conf%7bsmbclientrestorecmd%7d">$Conf{SmbClientRestoreCmd}</A>,
1645     <a href="#item_%24conf%7btarclientrestorecmd%7d">$Conf{TarClientRestoreCmd}</A> and <a href="#item_%24conf%7brsyncrestoreargs%7d">$Conf{RsyncRestoreArgs}</A> to undef.</p>
1646     </dd>
1647     <p></p>
1648     <dt><strong><a name="item_option_2_3a_download_zip_archive">Option 2: Download Zip archive</a></strong><br />
1649     </dt>
1650     <dd>
1651     With this option a zip file containing the selected files and directories
1652     is downloaded. The zip file can then be unpacked or individual files
1653     extracted as necessary on the host machine. The compression level can be
1654     specified. A value of 0 turns off compression.
1655     </dd>
1656     <dd>
1657     <p>When you select ``Download Zip File'' you should be prompted where to
1658     save the restore.zip file.</p>
1659     </dd>
1660     <dd>
1661     <p>BackupPC does not consider downloading a zip file as an actual
1662     restore operation, so the details are not saved for later browsing
1663     as in the first case. However, a mention that a zip file was
1664     downloaded by a particular user, and a list of the files, does
1665     appear in BackupPC's log file.</p>
1666     </dd>
1667     <p></p>
1668     <dt><strong><a name="item_option_3_3a_download_tar_archive">Option 3: Download Tar archive</a></strong><br />
1669     </dt>
1670     <dd>
1671     This is identical to the previous option, except a tar file is downloaded
1672     rather than a zip file (and there is currently no compression option).
1673     </dd>
1674     <p></p></dl>
1675     <p>
1676     </p>
1677     <h2><a name="commandline_restore_options">Command-line restore options</a></h2>
1678     <p>Apart from the CGI interface, BackupPC allows you to restore files
1679     and directories from the command line. The following programs can
1680     be used:</p>
1681     <dl>
1682     <dt><strong><a name="item_backuppc_zcat">BackupPC_zcat</a></strong><br />
1683     </dt>
1684     <dd>
1685     For each file name argument it inflates (uncompresses) the file and
1686     writes it to stdout. To use BackupPC_zcat you could give it the
1687     full file name, eg:
1688     </dd>
1689     <dd>
1690     <pre>
1691     __INSTALLDIR__/bin/BackupPC_zcat __TOPDIR__/pc/host/5/fc/fcraig/fexample.txt &gt; example.txt</pre>
1692     </dd>
1693     <dd>
1694     <p>It's your responsibility to make sure the file is really compressed:
1695     BackupPC_zcat doesn't check which backup the requested file is from.
1696     BackupPC_zcat returns a non-zero status if it fails to uncompress
1697     a file.</p>
1698     </dd>
1699     <p></p>
1700     <dt><strong><a name="item_backuppc_tarcreate">BackupPC_tarCreate</a></strong><br />
1701     </dt>
1702     <dd>
1703     BackupPC_tarCreate creates a tar file for any files or directories in
1704     a particular backup. Merging of incrementals is done automatically,
1705     so you don't need to worry about whether certain files appear in the
1706     incremental or full backup.
1707     </dd>
1708     <dd>
1709     <p>The usage is:</p>
1710     </dd>
1711     <dd>
1712     <pre>
1713     BackupPC_tarCreate [-t] [-h host] [-n dumpNum] [-s shareName]
1714     [-r pathRemove] [-p pathAdd] [-b BLOCKS] [-w writeBufSz]
1715     files/directories...</pre>
1716     </dd>
1717     <dd>
1718     <p>The command-line files and directories are relative to the specified
1719     shareName. The tar file is written to stdout.</p>
1720     </dd>
1721     <dd>
1722     <p>The required options are:</p>
1723     </dd>
1724     <dl>
1725     <dt><strong><a name="item__2dh_host">-h host</a></strong><br />
1726     </dt>
1727     <dd>
1728     host from which the tar archive is created
1729     </dd>
1730     <p></p>
1731     <dt><strong><a name="item__2dn_dumpnum">-n dumpNum</a></strong><br />
1732     </dt>
1733     <dd>
1734     dump number from which the tar archive is created
1735     </dd>
1736     <p></p>
1737     <dt><strong><a name="item__2ds_sharename">-s shareName</a></strong><br />
1738     </dt>
1739     <dd>
1740     share name from which the tar archive is created
1741     </dd>
1742     <p></p></dl>
1743     <p>Other options are:</p>
1744     <dl>
1745     <dt><strong>-t</strong><br />
1746     </dt>
1747     <dd>
1748     print summary totals
1749     </dd>
1750     <p></p>
1751     <dt><strong><a name="item__2dr_pathremove">-r pathRemove</a></strong><br />
1752     </dt>
1753     <dd>
1754     path prefix that will be replaced with pathAdd
1755     </dd>
1756     <p></p>
1757     <dt><strong><a name="item__2dp_pathadd">-p pathAdd</a></strong><br />
1758     </dt>
1759     <dd>
1760     new path prefix
1761     </dd>
1762     <p></p>
1763     <dt><strong><a name="item__2db_blocks">-b BLOCKS</a></strong><br />
1764     </dt>
1765     <dd>
1766     the tar block size, default is 20, meaning tar writes data in 20 * 512
1767     bytes chunks.
1768     </dd>
1769     <p></p>
1770     <dt><strong><a name="item__2dw_writebufsz">-w writeBufSz</a></strong><br />
1771     </dt>
1772     <dd>
1773     write buffer size, default 1048576 (1MB). You can increase this if
1774     you are trying to stream to a fast tape device.
1775     </dd>
1776     <p></p></dl>
1777     <p>The -h, -n and -s options specify which dump is used to generate
1778     the tar archive. The -r and -p options can be used to relocate
1779     the paths in the tar archive so extracted files can be placed
1780     in a location different from their original location.</p>
1781     <dt><strong><a name="item_backuppc_zipcreate">BackupPC_zipCreate</a></strong><br />
1782     </dt>
1783     <dd>
1784     BackupPC_zipCreate creates a zip file for any files or directories in
1785     a particular backup. Merging of incrementals is done automatically,
1786     so you don't need to worry about whether certain files appear in the
1787     incremental or full backup.
1788     </dd>
1789     <dd>
1790     <p>The usage is:</p>
1791     </dd>
1792     <dd>
1793     <pre>
1794     BackupPC_zipCreate [-t] [-h host] [-n dumpNum] [-s shareName]
1795     [-r pathRemove] [-p pathAdd] [-c compressionLevel]
1796     files/directories...</pre>
1797     </dd>
1798     <dd>
1799     <p>The command-line files and directories are relative to the specified
1800     shareName. The zip file is written to stdout.</p>
1801     </dd>
1802     <dd>
1803     <p>The required options are:</p>
1804     </dd>
1805     <dl>
1806     <dt><strong>-h host</strong><br />
1807     </dt>
1808     <dd>
1809     host from which the zip archive is created
1810     </dd>
1811     <p></p>
1812     <dt><strong>-n dumpNum</strong><br />
1813     </dt>
1814     <dd>
1815     dump number from which the zip archive is created
1816     </dd>
1817     <p></p>
1818     <dt><strong>-s shareName</strong><br />
1819     </dt>
1820     <dd>
1821     share name from which the zip archive is created
1822     </dd>
1823     <p></p></dl>
1824     <p>Other options are:</p>
1825     <dl>
1826     <dt><strong>-t</strong><br />
1827     </dt>
1828     <dd>
1829     print summary totals
1830     </dd>
1831     <p></p>
1832     <dt><strong>-r pathRemove</strong><br />
1833     </dt>
1834     <dd>
1835     path prefix that will be replaced with pathAdd
1836     </dd>
1837     <p></p>
1838     <dt><strong>-p pathAdd</strong><br />
1839     </dt>
1840     <dd>
1841     new path prefix
1842     </dd>
1843     <p></p>
1844     <dt><strong><a name="item__2dc_level">-c level</a></strong><br />
1845     </dt>
1846     <dd>
1847     compression level (default is 0, no compression)
1848     </dd>
1849     <p></p></dl>
1850     <p>The -h, -n and -s options specify which dump is used to generate
1851     the zip archive. The -r and -p options can be used to relocate
1852     the paths in the zip archive so extracted files can be placed
1853     in a location different from their original location.</p>
1854     </dl>
1855     <p>Each of these programs reside in __INSTALLDIR__/bin.</p>
1856     <p>
1857     <a href="#__index__"><small>Back to Top</small></a>
1858     </p>
1859     <hr />
1860     <h1><a name="archive_functions">Archive functions</a></h1>
1861     <p>BackupPC supports archiving to removable media. For users that require
1862     offsite backups, BackupPC can create archives that stream to tape
1863     devices, or create files of specified sizes to fit onto cd or dvd media.</p>
1864     <p>Each archive type is specified by a BackupPC host with its XferMethod
1865     set to 'archive'. This allows for multiple configurations at sites where
1866     there might be a combination of tape and cd/dvd backups being made.</p>
1867     <p>BackupPC provides a menu that allows one or more hosts to be archived.
1868     The most recent backup of each host is archived using BackupPC_tarCreate,
1869     and the output is optionally compressed and split into fixed-sized
1870     files (eg: 650MB).</p>
1871     <p>The archive for each host is done by default using
1872     __INSTALLDIR__/BackupPC_archiveHost. This script can be copied
1873     and customized as needed.</p>
1874     <p>
1875     </p>
1876     <h2><a name="configuring_an_archive_host">Configuring an Archive Host</a></h2>
1877     <p>To create an Archive Host, add it to the hosts file just as any other host
1878     and call it a name that best describes the type of archive, e.g. ArchiveDLT</p>
1879     <p>To tell BackupPC that the Host is for Archives, create a config.pl file in
1880     the Archive Hosts's pc directory, adding the following line:</p>
1881     <p><a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'archive';</p>
1882     <p>To further customise the archive's parameters you can adding the changed
1883     parameters in the host's config.pl file. The parameters are explained in
1884     the config.pl file. Parameters may be fixed or the user can be allowed
1885     to change them (eg: output device).</p>
1886     <p>The per-host archive command is <a href="#item_%24conf%7barchiveclientcmd%7d">$Conf{ArchiveClientCmd}</A>. By default
1887     this invokes</p>
1888     <pre>
1889     __INSTALLDIR__/BackupPC_archiveHost</pre>
1890     <p>which you can copy and customize as necessary.</p>
1891     <p>
1892     </p>
1893     <h2><a name="starting_an_archive">Starting an Archive</a></h2>
1894     <p>In the web interface, click on the Archive Host you wish to use. You will see a
1895     list of previous archives and a summary on each. By clicking the ``Start Archive''
1896     button you are presented with the list of hosts and the approximate backup size
1897     (note this is raw size, not projected compressed size) Select the hosts you wish
1898     to archive and press the ``Archive Selected Hosts'' button.</p>
1899     <p>The next screen allows you to adjust the parameters for this archive run.
1900     Press the ``Start the Archive'' to start archiving the selected hosts with the
1901     parameters displayed.</p>
1902     <p>
1903     <a href="#__index__"><small>Back to Top</small></a>
1904     </p>
1905     <hr />
1906     <h1><a name="backuppc_design">BackupPC Design</a></h1>
1907     <p>
1908     </p>
1909     <h2><a name="some_design_issues">Some design issues</a></h2>
1910     <dl>
1911     <dt><strong><a name="item_pooling_common_files">Pooling common files</a></strong><br />
1912     </dt>
1913     <dd>
1914     To quickly see if a file is already in the pool, an MD5 digest of the
1915     file length and contents is used as the file name in the pool. This
1916     can't guarantee a file is identical: it just reduces the search to
1917     often a single file or handful of files. A complete file comparison
1918     is always done to verify if two files are really the same.
1919     </dd>
1920     <dd>
1921     <p>Identical files on multiples backups are represented by hard links.
1922     Hardlinks are used so that identical files all refer to the same
1923     physical file on the server's disk. Also, hard links maintain
1924     reference counts so that BackupPC knows when to delete unused files
1925     from the pool.</p>
1926     </dd>
1927     <dd>
1928     <p>For the computer-science majors among you, you can think of the pooling
1929     system used by BackupPC as just a chained hash table stored on a (big)
1930     file system.</p>
1931     </dd>
1932     <p></p>
1933     <dt><strong><a name="item_the_hashing_function">The hashing function</a></strong><br />
1934     </dt>
1935     <dd>
1936     There is a tradeoff between how much of file is used for the MD5 digest
1937     and the time taken comparing all the files that have the same hash.
1938     </dd>
1939     <dd>
1940     <p>Using the file length and just the first 4096 bytes of the file for the
1941     MD5 digest produces some repetitions. One example: with 900,000 unique
1942     files in the pool, this hash gives about 7,000 repeated files, and in
1943     the worst case 500 files have the same hash. That's not bad: we only
1944     have to do a single file compare 99.2% of the time. But in the worst
1945     case we have to compare as many as 500 files checking for a match.</p>
1946     </dd>
1947     <dd>
1948     <p>With a modest increase in CPU time, if we use the file length and the
1949     first 256K of the file we now only have 500 repeated files and in the
1950     worst case around 20 files have the same hash. Furthermore, if we
1951     instead use the first and last 128K of the file (more specifically, the
1952     first and eighth 128K chunks for files larger than 1MB) we get only 300
1953     repeated files and in the worst case around 20 files have the same hash.</p>
1954     </dd>
1955     <dd>
1956     <p>Based on this experimentation, this is the hash function used by BackupPC.
1957     It is important that you don't change the hash function after files
1958     are already in the pool. Otherwise your pool will grow to twice the
1959     size until all the old backups (and all the old files with old hashes)
1960     eventually expire.</p>
1961     </dd>
1962     <p></p>
1963     <dt><strong><a name="item_compression">Compression</a></strong><br />
1964     </dt>
1965     <dd>
1966     BackupPC supports compression. It uses the deflate and inflate methods
1967     in the Compress::Zlib module, which is based on the zlib compression
1968     library (see <a href="http://www.gzip.org/zlib/">http://www.gzip.org/zlib/</a>).
1969     </dd>
1970     <dd>
1971     <p>The <a href="#item_%24conf%7bcompresslevel%7d">$Conf{CompressLevel}</A> setting specifies the compression level to use.
1972     Zero (0) means no compression. Compression levels can be from 1 (least
1973     cpu time, slightly worse compression) to 9 (most cpu time, slightly
1974     better compression). The recommended value is 3. Changing it to 5, for
1975     example, will take maybe 20% more cpu time and will get another 2-3%
1976     additional compression. Diminishing returns set in above 5. See the zlib
1977     documentation for more information about compression levels.</p>
1978     </dd>
1979     <dd>
1980     <p>BackupPC implements compression with minimal CPU load. Rather than
1981     compressing every incoming backup file and then trying to match it
1982     against the pool, BackupPC computes the MD5 digest based on the
1983     uncompressed file, and matches against the candidate pool files by
1984     comparing each uncompressed pool file against the incoming backup file.
1985     Since inflating a file takes roughly a factor of 10 less CPU time than
1986     deflating there is a big saving in CPU time.</p>
1987     </dd>
1988     <dd>
1989     <p>The combination of pooling common files and compression can yield
1990     a factor of 8 or more overall saving in backup storage.</p>
1991     </dd>
1992     <p></p></dl>
1993     <p>
1994     </p>
1995     <h2><a name="backuppc_operation">BackupPC operation</a></h2>
1996     <p>BackupPC reads the configuration information from
1997     __TOPDIR__/conf/config.pl. It then runs and manages all the backup
1998     activity. It maintains queues of pending backup requests, user backup
1999     requests and administrative commands. Based on the configuration various
2000     requests will be executed simultaneously.</p>
2001     <p>As specified by <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A>, BackupPC wakes up periodically
2002     to queue backups on all the PCs. This is a four step process:</p>
2003     <ol>
2004     <li>
2005     For each host and DHCP address backup requests are queued on the
2006     background command queue.
2007     <p></p>
2008     <li>
2009     For each PC, BackupPC_dump is forked. Several of these may be run in
2010     parallel, based on the configuration. First a ping is done to see if
2011     the machine is alive. If this is a DHCP address, nmblookup is run to
2012     get the netbios name, which is used as the host name. If DNS lookup
2013     fails, <a href="#item_%24conf%7bnmblookupfindhostcmd%7d">$Conf{NmbLookupFindHostCmd}</A> is run to find the IP address from
2014     the host name. The file __TOPDIR__/pc/$host/backups is read to decide
2015     whether a full or incremental backup needs to be run. If no backup is
2016     scheduled, or the ping to $host fails, then BackupPC_dump exits.
2017     <p>The backup is done using the specified XferMethod. Either samba's smbclient
2018     or tar over ssh/rsh/nfs piped into BackupPC_tarExtract, or rsync over ssh/rsh
2019     is run, or rsyncd is connected to, with the incoming data
2020     extracted to __TOPDIR__/pc/$host/new. The XferMethod output is put
2021     into __TOPDIR__/pc/$host/XferLOG.</p>
2022     <p>The letter in the XferLOG file shows the type of object, similar to the
2023     first letter of the modes displayed by ls -l:</p>
2024     <pre>
2025     d -&gt; directory
2026     l -&gt; symbolic link
2027     b -&gt; block special file
2028     c -&gt; character special file
2029     p -&gt; pipe file (fifo)
2030     nothing -&gt; regular file</pre>
2031     <p>The words mean:</p>
2032     <dl>
2033     <dt><strong><a name="item_create">create</a></strong><br />
2034     </dt>
2035     <dd>
2036     new for this backup (ie: directory or file not in pool)
2037     </dd>
2038     <p></p>
2039     <dt><strong><a name="item_pool">pool</a></strong><br />
2040     </dt>
2041     <dd>
2042     found a match in the pool
2043     </dd>
2044     <p></p>
2045     <dt><strong><a name="item_same">same</a></strong><br />
2046     </dt>
2047     <dd>
2048     file is identical to previous backup (contents were
2049     checksummed and verified during full dump).
2050     </dd>
2051     <p></p>
2052     <dt><strong><a name="item_skip">skip</a></strong><br />
2053     </dt>
2054     <dd>
2055     file skipped in incremental because attributes are the
2056     same (only displayed if <a href="#item_%24conf%7bxferloglevel%7d">$Conf{XferLogLevel}</A> &gt;= 2).
2057     </dd>
2058     <p></p></dl>
2059     <p>As BackupPC_tarExtract extracts the files from smbclient or tar, or as
2060     rsync runs, it checks each file in the backup to see if it is identical
2061     to an existing file from any previous backup of any PC. It does this
2062     without needed to write the file to disk. If the file matches an
2063     existing file, a hardlink is created to the existing file in the pool.
2064     If the file does not match any existing files, the file is written to
2065     disk and the file name is saved in __TOPDIR__/pc/$host/NewFileList for
2066     later processing by BackupPC_link. BackupPC_tarExtract and rsync can handle
2067     arbitrarily large files and multiple candidate matching files without
2068     needing to write the file to disk in the case of a match. This
2069     significantly reduces disk writes (and also reads, since the pool file
2070     comparison is done disk to memory, rather than disk to disk).</p>
2071     <p>Based on the configuration settings, BackupPC_dump checks each
2072     old backup to see if any should be removed. Any expired backups
2073     are moved to __TOPDIR__/trash for later removal by BackupPC_trashClean.</p>
2074     <li>
2075     For each complete, good, backup, BackupPC_link is run.
2076     To avoid race conditions as new files are linked into the
2077     pool area, only a single BackupPC_link program runs
2078     at a time and the rest are queued.
2079     <p>BackupPC_link reads the NewFileList written by BackupPC_dump and
2080     inspects each new file in the backup. It re-checks if there is a
2081     matching file in the pool (another BackupPC_link
2082     could have added the file since BackupPC_dump checked). If so, the file
2083     is removed and replaced by a hard link to the existing file. If the file
2084     is new, a hard link to the file is made in the pool area, so that this
2085     file is available for checking against each new file and new backup.</p>
2086     <p>Then, if <a href="#item_%24conf%7bincrfill%7d">$Conf{IncrFill}</A> is set (note that the default setting is
2087     off), for each incremental backup, hard links are made in the new
2088     backup to all files that were not extracted during the incremental
2089     backups. The means the incremental backup looks like a complete
2090     image of the PC (with the exception that files that were removed on
2091     the PC since the last full backup will still appear in the backup
2092     directory tree).</p>
2093     <p>The CGI interface knows how to merge unfilled incremental backups will
2094     the most recent prior filled (full) backup, giving the incremental
2095     backups a filled appearance. The default for <a href="#item_%24conf%7bincrfill%7d">$Conf{IncrFill}</A> is off,
2096     since there is no need to fill incremental backups. This saves
2097     some level of disk activity, since lots of extra hardlinks are no
2098     longer needed (and don't have to be deleted when the backup expires).</p>
2099     <p></p>
2100     <li>
2101     BackupPC_trashClean is always run in the background to remove any
2102     expired backups. Every 5 minutes it wakes up and removes all the files
2103     in __TOPDIR__/trash.
2104     <p>Also, once each night, BackupPC_nightly is run to complete some additional
2105     administrative tasks, such as cleaning the pool. This involves removing
2106     any files in the pool that only have a single hard link (meaning no backups
2107     are using that file). Again, to avoid race conditions, BackupPC_nightly
2108     is only run when there are no BackupPC_dump or BackupPC_link processes
2109     running. Therefore, when it is time to run BackupPC_nightly, no new
2110     backups are started and BackupPC waits until all backups have finished.
2111     Then BackupPC_nightly is run, and until it finishes no new backups are
2112     started. If BackupPC_nightly is slow, the settings</p>
2113     <p></p></ol>
2114     <p>BackupPC also listens for TCP connections on <a href="#item_%24conf%7bserverport%7d">$Conf{ServerPort}</A>, which
2115     is used by the CGI script BackupPC_Admin for status reporting and
2116     user-initiated backup or backup cancel requests.</p>
2117     <p>
2118     </p>
2119     <h2><a name="storage_layout">Storage layout</a></h2>
2120     <p>BackupPC resides in three directories:</p>
2121     <dl>
2122     <dt><strong><a name="item___installdir__">__INSTALLDIR__</a></strong><br />
2123     </dt>
2124     <dd>
2125     Perl scripts comprising BackupPC reside in __INSTALLDIR__/bin,
2126     libraries are in __INSTALLDIR__/lib and documentation
2127     is in __INSTALLDIR__/doc.
2128     </dd>
2129     <p></p>
2130     <dt><strong><a name="item___cgidir__">__CGIDIR__</a></strong><br />
2131     </dt>
2132     <dd>
2133     The CGI script BackupPC_Admin resides in this cgi binary directory.
2134     </dd>
2135     <p></p>
2136     <dt><strong><a name="item___topdir__">__TOPDIR__</a></strong><br />
2137     </dt>
2138     <dd>
2139     All of BackupPC's data (PC backup images, logs, configuration information)
2140     is stored below this directory.
2141     </dd>
2142     <p></p></dl>
2143     <p>Below __TOPDIR__ are several directories:</p>
2144     <dl>
2145     <dt><strong><a name="item___topdir___2fconf">__TOPDIR__/conf</a></strong><br />
2146     </dt>
2147     <dd>
2148     The directory __TOPDIR__/conf contains:
2149     </dd>
2150     <dl>
2151     <dt><strong><a name="item_config_2epl">config.pl</a></strong><br />
2152     </dt>
2153     <dd>
2154     Configuration file. See <a href="#configuration_file">Configuration file</a>
2155     below for more details.
2156     </dd>
2157     <p></p>
2158     <dt><strong><a name="item_hosts">hosts</a></strong><br />
2159     </dt>
2160     <dd>
2161     Hosts file, which lists all the PCs to backup.
2162     </dd>
2163     <p></p></dl>
2164     <dt><strong><a name="item___topdir___2flog">__TOPDIR__/log</a></strong><br />
2165     </dt>
2166     <dd>
2167     The directory __TOPDIR__/log contains:
2168     </dd>
2169     <dl>
2170     <dt><strong><a name="item_log">LOG</a></strong><br />
2171     </dt>
2172     <dd>
2173     Current (today's) log file output from BackupPC.
2174     </dd>
2175     <p></p>
2176     <dt><strong><a name="item_log_2e0_or_log_2e0_2ez">LOG.0 or LOG.0.z</a></strong><br />
2177     </dt>
2178     <dd>
2179     Yesterday's log file output. Log files are aged daily and compressed
2180     (if compression is enabled), and old LOG files are deleted.
2181     </dd>
2182     <p></p>
2183     <dt><strong><a name="item_backuppc_2epid">BackupPC.pid</a></strong><br />
2184     </dt>
2185     <dd>
2186     Contains BackupPC's process id.
2187     </dd>
2188     <p></p>
2189     <dt><strong><a name="item_status_2epl">status.pl</a></strong><br />
2190     </dt>
2191     <dd>
2192     A summary of BackupPC's status written periodically by BackupPC so
2193     that certain state information can be maintained if BackupPC is
2194     restarted. Should not be edited.
2195     </dd>
2196     <p></p>
2197     <dt><strong><a name="item_useremailinfo_2epl">UserEmailInfo.pl</a></strong><br />
2198     </dt>
2199     <dd>
2200     A summary of what email was last sent to each user, and when the
2201     last email was sent. Should not be edited.
2202     </dd>
2203     <p></p></dl>
2204     <dt><strong><a name="item___topdir___2ftrash">__TOPDIR__/trash</a></strong><br />
2205     </dt>
2206     <dd>
2207     Any directories and files below this directory are periodically deleted
2208     whenever BackupPC_trashClean checks. When a backup is aborted or when an
2209     old backup expires, BackupPC_dump simply moves the directory to
2210     __TOPDIR__/trash for later removal by BackupPC_trashClean.
2211     </dd>
2212     <p></p>
2213     <dt><strong><a name="item___topdir___2fpool">__TOPDIR__/pool</a></strong><br />
2214     </dt>
2215     <dd>
2216     All uncompressed files from PC backups are stored below __TOPDIR__/pool.
2217     Each file's name is based on the MD5 hex digest of the file contents.
2218     Specifically, for files less than 256K, the file length and the entire
2219     file is used. For files up to 1MB, the file length and the first and
2220     last 128K are used. Finally, for files longer than 1MB, the file length,
2221     and the first and eighth 128K chunks for the file are used.
2222     </dd>
2223     <dd>
2224     <p>Each file is stored in a subdirectory X/Y/Z, where X, Y, Z are the
2225     first 3 hex digits of the MD5 digest.</p>
2226     </dd>
2227     <dd>
2228     <p>For example, if a file has an MD5 digest of 123456789abcdef0,
2229     the file is stored in __TOPDIR__/pool/1/2/3/123456789abcdef0.</p>
2230     </dd>
2231     <dd>
2232     <p>The MD5 digest might not be unique (especially since not all the file's
2233     contents are used for files bigger than 256K). Different files that have
2234     the same MD5 digest are stored with a trailing suffix ``_n'' where n is
2235     an incrementing number starting at 0. So, for example, if two additional
2236     files were identical to the first, except the last byte was different,
2237     and assuming the file was larger than 1MB (so the MD5 digests are the
2238     same but the files are actually different), the three files would be
2239     stored as:</p>
2240     </dd>
2241     <dd>
2242     <pre>
2243     __TOPDIR__/pool/1/2/3/123456789abcdef0
2244     __TOPDIR__/pool/1/2/3/123456789abcdef0_0
2245     __TOPDIR__/pool/1/2/3/123456789abcdef0_1</pre>
2246     </dd>
2247     <dd>
2248     <p>Both BackupPC_dump (actually, BackupPC_tarExtract) and BackupPC_link are
2249     responsible for checking newly backed up files against the pool. For
2250     each file, the MD5 digest is used to generate a file name in the pool
2251     directory. If the file exists in the pool, the contents are compared.
2252     If there is no match, additional files ending in ``_n'' are checked.
2253     (Actually, BackupPC_tarExtract compares multiple candidate files in
2254     parallel.) If the file contents exactly match, the file is created by
2255     simply making a hard link to the pool file (this is done by
2256     BackupPC_tarExtract as the backup proceeds). Otherwise,
2257     BackupPC_tarExtract writes the new file to disk and a new hard link is
2258     made in the pool to the file (this is done later by BackupPC_link).</p>
2259     </dd>
2260     <dd>
2261     <p>Therefore, every file in the pool will have at least 2 hard links
2262     (one for the pool file and one for the backup file below __TOPDIR__/pc).
2263     Identical files from different backups or PCs will all be linked to
2264     the same file. When old backups are deleted, some files in the pool
2265     might only have one link. BackupPC_nightly checks the entire pool
2266     and removes all files that have only a single link, thereby recovering
2267     the storage for that file.</p>
2268     </dd>
2269     <dd>
2270     <p>One other issue: zero length files are not pooled, since there are a lot
2271     of these files and on most file systems it doesn't save any disk space
2272     to turn these files into hard links.</p>
2273     </dd>
2274     <p></p>
2275     <dt><strong><a name="item___topdir___2fcpool">__TOPDIR__/cpool</a></strong><br />
2276     </dt>
2277     <dd>
2278     All compressed files from PC backups are stored below __TOPDIR__/cpool.
2279     Its layout is the same as __TOPDIR__/pool, and the hashing function
2280     is the same (and, importantly, based on the uncompressed file, not
2281     the compressed file).
2282     </dd>
2283     <p></p>
2284     <dt><strong><a name="item___topdir___2fpc_2f_24host">__TOPDIR__/pc/$host</a></strong><br />
2285     </dt>
2286     <dd>
2287     For each PC $host, all the backups for that PC are stored below
2288     the directory __TOPDIR__/pc/$host. This directory contains the
2289     following files:
2290     </dd>
2291     <dl>
2292     <dt><strong>LOG</strong><br />
2293     </dt>
2294     <dd>
2295     Current log file for this PC from BackupPC_dump.
2296     </dd>
2297     <p></p>
2298     <dt><strong>LOG.0 or LOG.0.z</strong><br />
2299     </dt>
2300     <dd>
2301     Last month's log file. Log files are aged monthly and compressed
2302     (if compression is enabled), and old LOG files are deleted.
2303     </dd>
2304     <p></p>
2305     <dt><strong><a name="item_xfererr_or_xfererr_2ez">XferERR or XferERR.z</a></strong><br />
2306     </dt>
2307     <dd>
2308     Output from the transport program (ie: smbclient, tar or rsync)
2309     for the most recent failed backup.
2310     </dd>
2311     <p></p>
2312     <dt><strong><a name="item_new">new</a></strong><br />
2313     </dt>
2314     <dd>
2315     Subdirectory in which the current backup is stored. This
2316     directory is renamed if the backup succeeds.
2317     </dd>
2318     <p></p>
2319     <dt><strong><a name="item_xferlog_or_xferlog_2ez">XferLOG or XferLOG.z</a></strong><br />
2320     </dt>
2321     <dd>
2322     Output from the transport program (ie: smbclient, tar or rsync)
2323     for the current backup.
2324     </dd>
2325     <p></p>
2326     <dt><strong><a name="item_nnn">nnn (an integer)</a></strong><br />
2327     </dt>
2328     <dd>
2329     Successful backups are in directories numbered sequentially starting at 0.
2330     </dd>
2331     <p></p>
2332     <dt><strong><a name="item_xferlog_2ennn_or_xferlog_2ennn_2ez">XferLOG.nnn or XferLOG.nnn.z</a></strong><br />
2333     </dt>
2334     <dd>
2335     Output from the transport program (ie: smbclient, tar or rsync)
2336     corresponding to backup number nnn.
2337     </dd>
2338     <p></p>
2339     <dt><strong><a name="item_restoreinfo_2ennn">RestoreInfo.nnn</a></strong><br />
2340     </dt>
2341     <dd>
2342     Information about restore request #nnn including who, what, when, and
2343     why. This file is in Data::Dumper format. (Note that the restore
2344     numbers are not related to the backup number.)
2345     </dd>
2346     <p></p>
2347     <dt><strong><a name="item_restorelog_2ennn_2ez">RestoreLOG.nnn.z</a></strong><br />
2348     </dt>
2349     <dd>
2350     Output from smbclient, tar or rsync during restore #nnn. (Note that the restore
2351     numbers are not related to the backup number.)
2352     </dd>
2353     <p></p>
2354     <dt><strong><a name="item_archiveinfo_2ennn">ArchiveInfo.nnn</a></strong><br />
2355     </dt>
2356     <dd>
2357     Information about archive request #nnn including who, what, when, and
2358     why. This file is in Data::Dumper format. (Note that the archive
2359     numbers are not related to the restore or backup number.)
2360     </dd>
2361     <p></p>
2362     <dt><strong><a name="item_archivelog_2ennn_2ez">ArchiveLOG.nnn.z</a></strong><br />
2363     </dt>
2364     <dd>
2365     Output from archive #nnn. (Note that the archive numbers are not related
2366     to the backup or restore number.)
2367     </dd>
2368     <p></p>
2369     <dt><strong>config.pl</strong><br />
2370     </dt>
2371     <dd>
2372     Optional configuration settings specific to this host. Settings in this
2373     file override the main configuration file.
2374     </dd>
2375     <p></p>
2376     <dt><strong><a name="item_backups">backups</a></strong><br />
2377     </dt>
2378     <dd>
2379     A tab-delimited ascii table listing information about each successful
2380     backup, one per row. The columns are:
2381     </dd>
2382     <dl>
2383     <dt><strong><a name="item_num">num</a></strong><br />
2384     </dt>
2385     <dd>
2386     The backup number, an integer that starts at 0 and increments
2387     for each successive backup. The corresponding backup is stored
2388     in the directory num (eg: if this field is 5, then the backup is
2389     stored in __TOPDIR__/pc/$host/5).
2390     </dd>
2391     <p></p>
2392     <dt><strong><a name="item_type">type</a></strong><br />
2393     </dt>
2394     <dd>
2395     Set to ``full'' or ``incr'' for full or incremental backup.
2396     </dd>
2397     <p></p>
2398     <dt><strong><a name="item_starttime">startTime</a></strong><br />
2399     </dt>
2400     <dd>
2401     Start time of the backup in unix seconds.
2402     </dd>
2403     <p></p>
2404     <dt><strong><a name="item_endtime">endTime</a></strong><br />
2405     </dt>
2406     <dd>
2407     Stop time of the backup in unix seconds.
2408     </dd>
2409     <p></p>
2410     <dt><strong><a name="item_nfiles">nFiles</a></strong><br />
2411     </dt>
2412     <dd>
2413     Number of files backed up (as reported by smbclient, tar or rsync).
2414     </dd>
2415     <p></p>
2416     <dt><strong><a name="item_size">size</a></strong><br />
2417     </dt>
2418     <dd>
2419     Total file size backed up (as reported by smbclient, tar or rsync).
2420     </dd>
2421     <p></p>
2422     <dt><strong><a name="item_nfilesexist">nFilesExist</a></strong><br />
2423     </dt>
2424     <dd>
2425     Number of files that were already in the pool
2426     (as determined by BackupPC_dump and BackupPC_link).
2427     </dd>
2428     <p></p>
2429     <dt><strong><a name="item_sizeexist">sizeExist</a></strong><br />
2430     </dt>
2431     <dd>
2432     Total size of files that were already in the pool
2433     (as determined by BackupPC_dump and BackupPC_link).
2434     </dd>
2435     <p></p>
2436     <dt><strong><a name="item_nfilesnew">nFilesNew</a></strong><br />
2437     </dt>
2438     <dd>
2439     Number of files that were not in the pool
2440     (as determined by BackupPC_link).
2441     </dd>
2442     <p></p>
2443     <dt><strong><a name="item_sizenew">sizeNew</a></strong><br />
2444     </dt>
2445     <dd>
2446     Total size of files that were not in the pool
2447     (as determined by BackupPC_link).
2448     </dd>
2449     <p></p>
2450     <dt><strong><a name="item_xfererrs">xferErrs</a></strong><br />
2451     </dt>
2452     <dd>
2453     Number of errors or warnings from smbclient, tar or rsync.
2454     </dd>
2455     <p></p>
2456     <dt><strong><a name="item_xferbadfile">xferBadFile</a></strong><br />
2457     </dt>
2458     <dd>
2459     Number of errors from smbclient that were bad file errors (zero otherwise).
2460     </dd>
2461     <p></p>
2462     <dt><strong><a name="item_xferbadshare">xferBadShare</a></strong><br />
2463     </dt>
2464     <dd>
2465     Number of errors from smbclient that were bad share errors (zero otherwise).
2466     </dd>
2467     <p></p>
2468     <dt><strong><a name="item_tarerrs">tarErrs</a></strong><br />
2469     </dt>
2470     <dd>
2471     Number of errors from BackupPC_tarExtract.
2472     </dd>
2473     <p></p>
2474     <dt><strong><a name="item_compress">compress</a></strong><br />
2475     </dt>
2476     <dd>
2477     The compression level used on this backup. Zero or empty means no
2478     compression.
2479     </dd>
2480     <p></p>
2481     <dt><strong><a name="item_sizeexistcomp">sizeExistComp</a></strong><br />
2482     </dt>
2483     <dd>
2484     Total compressed size of files that were already in the pool
2485     (as determined by BackupPC_dump and BackupPC_link).
2486     </dd>
2487     <p></p>
2488     <dt><strong><a name="item_sizenewcomp">sizeNewComp</a></strong><br />
2489     </dt>
2490     <dd>
2491     Total compressed size of files that were not in the pool
2492     (as determined by BackupPC_link).
2493     </dd>
2494     <p></p>
2495     <dt><strong><a name="item_nofill">noFill</a></strong><br />
2496     </dt>
2497     <dd>
2498     Set if this backup has not been filled in with the most recent
2499     previous filled or full backup. See <a href="#item_%24conf%7bincrfill%7d">$Conf{IncrFill}</A>.
2500     </dd>
2501     <p></p>
2502     <dt><strong><a name="item_fillfromnum">fillFromNum</a></strong><br />
2503     </dt>
2504     <dd>
2505     If this backup was filled (ie: noFill is 0) then this is the
2506     number of the backup that it was filled from
2507     </dd>
2508     <p></p>
2509     <dt><strong><a name="item_mangle">mangle</a></strong><br />
2510     </dt>
2511     <dd>
2512     Set if this backup has mangled file names and attributes. Always
2513     true for backups in v1.4.0 and above. False for all backups prior
2514     to v1.4.0.
2515     </dd>
2516     <p></p>
2517     <dt><strong><a name="item_xfermethod">xferMethod</a></strong><br />
2518     </dt>
2519     <dd>
2520     Set to the value of <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> when this dump was done.
2521     </dd>
2522     <p></p>
2523     <dt><strong><a name="item_level">level</a></strong><br />
2524     </dt>
2525     <dd>
2526     The level of this dump. A full dump is level 0. Currently incrementals
2527     are 1. But when multi-level incrementals are supported this will reflect
2528     each dump's incremental level.
2529     </dd>
2530     <p></p></dl>
2531     <dt><strong><a name="item_restores">restores</a></strong><br />
2532     </dt>
2533     <dd>
2534     A tab-delimited ascii table listing information about each requested
2535     restore, one per row. The columns are:
2536     </dd>
2537     <dl>
2538     <dt><strong>num</strong><br />
2539     </dt>
2540     <dd>
2541     Restore number (matches the suffix of the RestoreInfo.nnn and
2542     RestoreLOG.nnn.z file), unrelated to the backup number.
2543     </dd>
2544     <p></p>
2545     <dt><strong>startTime</strong><br />
2546     </dt>
2547     <dd>
2548     Start time of the restore in unix seconds.
2549     </dd>
2550     <p></p>
2551     <dt><strong>endTime</strong><br />
2552     </dt>
2553     <dd>
2554     End time of the restore in unix seconds.
2555     </dd>
2556     <p></p>
2557     <dt><strong><a name="item_result">result</a></strong><br />
2558     </dt>
2559     <dd>
2560     Result (ok or failed).
2561     </dd>
2562     <p></p>
2563     <dt><strong><a name="item_errormsg">errorMsg</a></strong><br />
2564     </dt>
2565     <dd>
2566     Error message if restore failed.
2567     </dd>
2568     <p></p>
2569     <dt><strong>nFiles</strong><br />
2570     </dt>
2571     <dd>
2572     Number of files restored.
2573     </dd>
2574     <p></p>
2575     <dt><strong>size</strong><br />
2576     </dt>
2577     <dd>
2578     Size in bytes of the restored files.
2579     </dd>
2580     <p></p>
2581     <dt><strong><a name="item_tarcreateerrs">tarCreateErrs</a></strong><br />
2582     </dt>
2583     <dd>
2584     Number of errors from BackupPC_tarCreate during restore.
2585     </dd>
2586     <p></p>
2587     <dt><strong>xferErrs</strong><br />
2588     </dt>
2589     <dd>
2590     Number of errors from smbclient, tar or rsync during restore.
2591     </dd>
2592     <p></p></dl>
2593     <dt><strong><a name="item_archives">archives</a></strong><br />
2594     </dt>
2595     <dd>
2596     A tab-delimited ascii table listing information about each requested
2597     archive, one per row. The columns are:
2598     </dd>
2599     <dl>
2600     <dt><strong>num</strong><br />
2601     </dt>
2602     <dd>
2603     Archive number (matches the suffix of the ArchiveInfo.nnn and
2604     ArchiveLOG.nnn.z file), unrelated to the backup or restore number.
2605     </dd>
2606     <p></p>
2607     <dt><strong>startTime</strong><br />
2608     </dt>
2609     <dd>
2610     Start time of the restore in unix seconds.
2611     </dd>
2612     <p></p>
2613     <dt><strong>endTime</strong><br />
2614     </dt>
2615     <dd>
2616     End time of the restore in unix seconds.
2617     </dd>
2618     <p></p>
2619     <dt><strong>result</strong><br />
2620     </dt>
2621     <dd>
2622     Result (ok or failed).
2623     </dd>
2624     <p></p>
2625     <dt><strong>errorMsg</strong><br />
2626     </dt>
2627     <dd>
2628     Error message if archive failed.
2629     </dd>
2630     <p></p></dl>
2631     </dl>
2632     </dl>
2633     <p>
2634     </p>
2635     <h2><a name="compressed_file_format">Compressed file format</a></h2>
2636     <p>The compressed file format is as generated by Compress::Zlib::deflate
2637     with one minor, but important, tweak. Since Compress::Zlib::inflate
2638     fully inflates its argument in memory, it could take large amounts of
2639     memory if it was inflating a highly compressed file. For example, a
2640     200MB file of 0x0 bytes compresses to around 200K bytes. If
2641     Compress::Zlib::inflate was called with this single 200K buffer, it
2642     would need to allocate 200MB of memory to return the result.</p>
2643     <p>BackupPC watches how efficiently a file is compressing. If a big file
2644     has very high compression (meaning it will use too much memory when it
2645     is inflated), BackupPC calls the <code>flush()</code> method, which gracefully
2646     completes the current compression. BackupPC then starts another
2647     deflate and simply appends the output file. So the BackupPC compressed
2648     file format is one or more concatenated deflations/flushes. The specific
2649     ratios that BackupPC uses is that if a 6MB chunk compresses to less
2650     than 64K then a flush will be done.</p>
2651     <p>Back to the example of the 200MB file of 0x0 bytes. Adding flushes
2652     every 6MB adds only 200 or so bytes to the 200K output. So the
2653     storage cost of flushing is negligible.</p>
2654     <p>To easily decompress a BackupPC compressed file, the script
2655     BackupPC_zcat can be found in __INSTALLDIR__/bin. For each
2656     file name argument it inflates the file and writes it to stdout.</p>
2657     <p>
2658     </p>
2659     <h2><a name="rsync_checksum_caching">Rsync checksum caching</a></h2>
2660     <p>An incremental backup with rsync compares attributes on the client
2661     with the last full backup. Any files with identical attributes
2662     are skipped. A full backup with rsync sets the --ignore-times
2663     option, which causes every file to be examined independent of
2664     attributes.</p>
2665     <p>Each file is examined by generating block checksums (default 2K
2666     blocks) on the receiving side (that's the BackupPC side), sending
2667     those checksums to the client, where the remote rsync matches those
2668     checksums with the corresponding file. The matching blocks and new
2669     data is sent back, allowing the client file to be reassembled.
2670     A checksum for the entire file is sent to as an extra check the
2671     the reconstructed file is correct.</p>
2672     <p>This results in significant disk IO and computation for BackupPC:
2673     every file in a full backup, or any file with non-matching attributes
2674     in an incremental backup, needs to be uncompressed, block checksums
2675     computed and sent. Then the receiving side reassembles the file and
2676     has to verify the whole-file checksum. Even if the file is identical,
2677     prior to 2.1.0, BackupPC had to read and uncompress the file twice,
2678     once to compute the block checksums and later to verify the whole-file
2679     checksum.</p>
2680     <p>Starting in 2.1.0, BackupPC supports optional checksum caching,
2681     which means the block and file checksums only need to be computed
2682     once for each file. This results in a significant performance
2683     improvement. This only works for compressed pool files.
2684     It is enabled by adding</p>
2685     <pre>
2686     '--checksum-seed=32761',</pre>
2687     <p>to <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A> and <a href="#item_%24conf%7brsyncrestoreargs%7d">$Conf{RsyncRestoreArgs}</A>.</p>
2688     <p>Rsync versions prior to and including rsync-2.6.2 need a small patch to
2689     add support for the --checksum-seed option. This patch is available in
2690     the cygwin-rsyncd package at <a href="http://backuppc.sourceforge.net">http://backuppc.sourceforge.net</a>.
2691     This patch is already included in rsync CVS, so it will be standard
2692     in future versions of rsync.</p>
2693     <p>When this option is present, BackupPC will add block and file checksums
2694     to the compressed pool file the next time a pool file is used and it
2695     doesn't already have cached checksums. The first time a new file is
2696     written to the pool, the checksums are not appended. The next time
2697     checksums are needed for a file, they are computed and added. So the
2698     full performance benefit of checksum caching won't be noticed until the
2699     third time a pool file is used (eg: the third full backup).</p>
2700     <p>With checksum caching enabled, there is a risk that should a file's contents
2701     in the pool be corrupted due to a disk problem, but the cached checksums
2702     are still correct, the corruption will not be detected by a full backup,
2703     since the file contents are no longer read and compared. To reduce the
2704     chance that this remains undetected, BackupPC can recheck cached checksums
2705     for a fraction of the files. This fraction is set with the
2706     <a href="#item_%24conf%7brsynccsumcacheverifyprob%7d">$Conf{RsyncCsumCacheVerifyProb}</A> setting. The default value of 0.01 means
2707     that 1% of the time a file's checksums are read, the checksums are verified.
2708     This reduces performance slightly, but, over time, ensures that files
2709     contents are in sync with the cached checksums.</p>
2710     <p>The format of the cached checksum data can be discovered by looking at
2711     the code. Basically, the first byte of the compressed file is changed
2712     to denote that checksums are appended. The block and file checksum
2713     data, plus some other information and magic word, are appended to the
2714     compressed file. This allows the cache update to be done in-place.</p>
2715     <p>
2716     </p>
2717     <h2><a name="file_name_mangling">File name mangling</a></h2>
2718     <p>Backup file names are stored in ``mangled'' form. Each node of
2719     a path is preceded by ``f'' (mnemonic: file), and special characters
2720     (\n, \r, % and /) are URI-encoded as ``%xx'', where xx is the ascii
2721     character's hex value. So c:/craig/example.txt is now stored as
2722     fc/fcraig/fexample.txt.</p>
2723     <p>This was done mainly so meta-data could be stored alongside the backup
2724     files without name collisions. In particular, the attributes for the
2725     files in a directory are stored in a file called ``attrib'', and mangling
2726     avoids file name collisions (I discarded the idea of having a duplicate
2727     directory tree for every backup just to store the attributes). Other
2728     meta-data (eg: rsync checksums) could be stored in file names preceded
2729     by, eg, ``c''. There are two other benefits to mangling: the share name
2730     might contain ``/'' (eg: ``/home/craig'' for tar transport), and I wanted
2731     that represented as a single level in the storage tree. Secondly, as
2732     files are written to NewFileList for later processing by BackupPC_link,
2733     embedded newlines in the file's path will cause problems which are
2734     avoided by mangling.</p>
2735     <p>The CGI script undoes the mangling, so it is invisible to the user.
2736     Old (unmangled) backups are still supported by the CGI
2737     interface.</p>
2738     <p>
2739     </p>
2740     <h2><a name="special_files">Special files</a></h2>
2741     <p>Linux/unix file systems support several special file types: symbolic
2742     links, character and block device files, fifos (pipes) and unix-domain
2743     sockets. All except unix-domain sockets are supported by BackupPC
2744     (there's no point in backing up or restoring unix-domain sockets since
2745     they only have meaning after a process creates them). Symbolic links are
2746     stored as a plain file whose contents are the contents of the link (not
2747     the file it points to). This file is compressed and pooled like any
2748     normal file. Character and block device files are also stored as plain
2749     files, whose contents are two integers separated by a comma; the numbers
2750     are the major and minor device number. These files are compressed and
2751     pooled like any normal file. Fifo files are stored as empty plain files
2752     (which are not pooled since they have zero size). In all cases, the
2753     original file type is stored in the attrib file so it can be correctly
2754     restored.</p>
2755     <p>Hardlinks are also supported. When GNU tar first encounters a file with
2756     more than one link (ie: hardlinks) it dumps it as a regular file. When
2757     it sees the second and subsequent hardlinks to the same file, it dumps
2758     just the hardlink information. BackupPC correctly recognizes these
2759     hardlinks and stores them just like symlinks: a regular text file
2760     whose contents is the path of the file linked to. The CGI script
2761     will download the original file when you click on a hardlink.</p>
2762     <p>Also, BackupPC_tarCreate has enough magic to re-create the hardlinks
2763     dynamically based on whether or not the original file and hardlinks
2764     are both included in the tar file. For example, imagine a/b/x is a
2765     hardlink to a/c/y. If you use BackupPC_tarCreate to restore directory
2766     a, then the tar file will include a/b/x as the original file and a/c/y
2767     will be a hardlink to a/b/x. If, instead you restore a/c, then the
2768     tar file will include a/c/y as the original file, not a hardlink.</p>
2769     <p>
2770     </p>
2771     <h2><a name="attribute_file_format">Attribute file format</a></h2>
2772     <p>The unix attributes for the contents of a directory (all the files and
2773     directories in that directory) are stored in a file called attrib.
2774     There is a single attrib file for each directory in a backup.
2775     For example, if c:/craig contains a single file c:/craig/example.txt,
2776     that file would be stored as fc/fcraig/fexample.txt and there would be an
2777     attribute file in fc/fcraig/attrib (and also fc/attrib and ./attrib).
2778     The file fc/fcraig/attrib would contain a single entry containing the
2779     attributes for fc/fcraig/fexample.txt.</p>
2780     <p>The attrib file starts with a magic number, followed by the
2781     concatenation of the following information for each file:</p>
2782     <ul>
2783     <li>
2784     File name length in perl's pack ``w'' format (variable length base 128).
2785     <p></p>
2786     <li>
2787     File name.
2788     <p></p>
2789     <li>
2790     The unix file type, mode, uid, gid and file size divided by 4GB and
2791     file size modulo 4GB (type mode uid gid sizeDiv4GB sizeMod4GB),
2792     in perl's pack ``w'' format (variable length base 128).
2793     <p></p>
2794     <li>
2795     The unix mtime (unix seconds) in perl's pack ``N'' format (32 bit integer).
2796     <p></p></ul>
2797     <p>The attrib file is also compressed if compression is enabled.
2798     See the lib/BackupPC/Attrib.pm module for full details.</p>
2799     <p>Attribute files are pooled just like normal backup files. This saves
2800     space if all the files in a directory have the same attributes across
2801     multiple backups, which is common.</p>
2802     <p>
2803     </p>
2804     <h2><a name="optimizations">Optimizations</a></h2>
2805     <p>BackupPC doesn't care about the access time of files in the pool
2806     since it saves attribute meta-data separate from the files. Since
2807     BackupPC mostly does reads from disk, maintaining the access time of
2808     files generates a lot of unnecessary disk writes. So, provided
2809     BackupPC has a dedicated data disk, you should consider mounting
2810     BackupPC's data directory with the noatime attribute (see mount(1)).</p>
2811     <p>
2812     </p>
2813     <h2><a name="limitations">Limitations</a></h2>
2814     <p>BackupPC isn't perfect (but it is getting better). Please see
2815     <a href="http://backuppc.sourceforge.net/faq/limitations.html">http://backuppc.sourceforge.net/faq/limitations.html</a> for a
2816     discussion of some of BackupPC's limitations.</p>
2817     <p>
2818     </p>
2819     <h2><a name="security_issues">Security issues</a></h2>
2820     <p>Please see <a href="http://backuppc.sourceforge.net/faq/security.html">http://backuppc.sourceforge.net/faq/security.html</a> for a
2821     discussion of some of various security issues.</p>
2822     <p>
2823     <a href="#__index__"><small>Back to Top</small></a>
2824     </p>
2825     <hr />
2826     <h1><a name="configuration_file">Configuration File</a></h1>
2827     <p>The BackupPC configuration file resides in __TOPDIR__/conf/config.pl.
2828     Optional per-PC configuration files reside in __TOPDIR__/pc/$host/config.pl.
2829     This file can be used to override settings just for a particular PC.</p>
2830     <p>
2831     </p>
2832     <h2><a name="modifying_the_main_configuration_file">Modifying the main configuration file</a></h2>
2833     <p>The configuration file is a perl script that is executed by BackupPC, so
2834     you should be careful to preserve the file syntax (punctuation, quotes
2835     etc) when you edit it. It is recommended that you use CVS, RCS or some
2836     other method of source control for changing config.pl.</p>
2837     <p>BackupPC reads or re-reads the main configuration file and
2838     the hosts file in three cases:</p>
2839     <ul>
2840     <li>
2841     Upon startup.
2842     <p></p>
2843     <li>
2844     When BackupPC is sent a HUP (-1) signal. Assuming you installed the
2845     init.d script, you can also do this with ``/etc/init.d/backuppc reload''.
2846     <p></p>
2847     <li>
2848     When the modification time of config.pl file changes. BackupPC
2849     checks the modification time once during each regular wakeup.
2850     <p></p></ul>
2851     <p>Whenever you change the configuration file you can either do
2852     a kill -HUP BackupPC_pid or simply wait until the next regular
2853     wakeup period.</p>
2854     <p>Each time the configuration file is re-read a message is reported in the
2855     LOG file, so you can tail it (or view it via the CGI interface) to make
2856     sure your kill -HUP worked. Errors in parsing the configuration file are
2857     also reported in the LOG file.</p>
2858     <p>The optional per-PC configuration file (__TOPDIR__/pc/$host/config.pl)
2859     is read whenever it is needed by BackupPC_dump, BackupPC_link and others.</p>
2860     <p>
2861     </p>
2862     <h2><a name="configuration_file_includes">Configuration file includes</a></h2>
2863     <p>If you have a heterogeneous set of clients (eg: a variety of WinXX and
2864     linux/unix machines) you will need to create host-specific config.pl files
2865     for some or all of these machines to customize the default settings from
2866     the master config.pl file (at a minimum to set <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A>).</p>
2867     <p>Since the config.pl file is just regular perl code, you can include
2868     one config file from another. For example, imagine you had three general
2869     classes of machines: WinXX desktops, linux machines in the DMZ and
2870     linux desktops. You could create three config files in __TOPDIR__/conf:</p>
2871     <pre>
2872     __TOPDIR__/conf/ConfigWinDesktop.pl
2873     __TOPDIR__/conf/ConfigLinuxDMZ.pl
2874     __TOPDIR__/conf/ConfigLinuxDesktop.pl</pre>
2875     <p>From each client's directory you can either add a symbolic link to
2876     the appropriate config file:</p>
2877     <pre>
2878     cd __TOPDIR__/pc/$host
2879     ln -s ../../conf/ConfigWinDesktop.pl config.pl</pre>
2880     <p>or, better yet, create a config.pl file in __TOPDIR__/pc/$host
2881     that includes the default config.pl file using perl's ``do''
2882     command:</p>
2883     <pre>
2884     do &quot;__TOPDIR__/conf/ConfigWinDesktop.pl&quot;;</pre>
2885     <p>This alternative allows you to set other configuration options
2886     specific to each host after the ``do'' command (perhaps even
2887     overriding the settings in the included file).</p>
2888     <p>Note that you could also include snippets of configuration settings
2889     from the main configuration file. However, be aware that the
2890     modification-time checking that BackupPC does only applies to the
2891     main configuration file: if you change one of the included files,
2892     BackupPC won't notice. You will need to either touch the main
2893     configuration file too, or send BackupPC a HUP (-1) signal.</p>
2894     <p>
2895     <a href="#__index__"><small>Back to Top</small></a>
2896     </p>
2897     <hr />
2898     <h1><a name="configuration_parameters">Configuration Parameters</a></h1>
2899     <p>The configuration parameters are divided into five general groups.
2900     The first group (general server configuration) provides general
2901     configuration for BackupPC. The next two groups describe what to
2902     backup, when to do it, and how long to keep it. The fourth group
2903     are settings for email reminders, and the final group contains
2904     settings for the CGI interface.</p>
2905     <p>All configuration settings in the second through fifth groups can
2906     be overridden by the per-PC config.pl file.</p>
2907     <p>
2908     </p>
2909     <h2><a name="general_server_configuration">General server configuration</a></h2>
2910     <dl>
2911     <dt><strong><a name="item_%24conf%7bserverhost%7d">$Conf{ServerHost} = '';</a></strong><br />
2912     </dt>
2913     <dd>
2914     Host name on which the BackupPC server is running.
2915     </dd>
2916     <p></p>
2917     <dt><strong><a name="item_%24conf%7bserverport%7d">$Conf{ServerPort} = -1;</a></strong><br />
2918     </dt>
2919     <dd>
2920     TCP port number on which the BackupPC server listens for and accepts
2921     connections. Normally this should be disabled (set to -1). The TCP
2922     port is only needed if apache runs on a different machine from BackupPC.
2923     In that case, set this to any spare port number over 1024 (eg: 2359).
2924     If you enable the TCP port, make sure you set <a href="#item_%24conf%7bservermesgsecret%7d">$Conf{ServerMesgSecret}</A>
2925     too!
2926     </dd>
2927     <p></p>
2928     <dt><strong><a name="item_%24conf%7bservermesgsecret%7d">$Conf{ServerMesgSecret} = '';</a></strong><br />
2929     </dt>
2930     <dd>
2931     Shared secret to make the TCP port secure. Set this to a hard to guess
2932     string if you enable the TCP port (ie: <a href="#item_%24conf%7bserverport%7d">$Conf{ServerPort}</A> &gt; 0).
2933     </dd>
2934     <dd>
2935     <p>To avoid possible attacks via the TCP socket interface, every client
2936     message is protected by an MD5 digest. The MD5 digest includes four
2937     items:
2938     - a seed that is sent to the client when the connection opens
2939     - a sequence number that increments for each message
2940     - a shared secret that is stored in <a href="#item_%24conf%7bservermesgsecret%7d">$Conf{ServerMesgSecret}</A>
2941     - the message itself.</p>
2942     </dd>
2943     <dd>
2944     <p>The message is sent in plain text preceded by the MD5 digest. A
2945     snooper can see the plain-text seed sent by BackupPC and plain-text
2946     message from the client, but cannot construct a valid MD5 digest since
2947     the secret <a href="#item_%24conf%7bservermesgsecret%7d">$Conf{ServerMesgSecret}</A> is unknown. A replay attack is
2948     not possible since the seed changes on a per-connection and
2949     per-message basis.</p>
2950     </dd>
2951     <p></p>
2952     <dt><strong><a name="item_%24conf%7bmypath%7d">$Conf{MyPath} = '/bin';</a></strong><br />
2953     </dt>
2954     <dd>
2955     PATH setting for BackupPC. An explicit value is necessary
2956     for taint mode. Value shouldn't matter too much since
2957     all execs use explicit paths. However, taint mode in perl
2958     will complain if this directory is world writable.
2959     </dd>
2960     <p></p>
2961     <dt><strong><a name="item_%24conf%7bumaskmode%7d">$Conf{UmaskMode} = 027;</a></strong><br />
2962     </dt>
2963     <dd>
2964     Permission mask for directories and files created by BackupPC.
2965     Default value prevents any access from group other, and prevents
2966     group write.
2967     </dd>
2968     <p></p>
2969     <dt><strong><a name="item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule} = [1..23];</a></strong><br />
2970     </dt>
2971     <dd>
2972     Times at which we wake up, check all the PCs, and schedule necessary
2973     backups. Times are measured in hours since midnight. Can be
2974     fractional if necessary (eg: 4.25 means 4:15am).
2975     </dd>
2976     <dd>
2977     <p>If the hosts you are backing up are always connected to the network
2978     you might have only one or two wakeups each night. This will keep
2979     the backup activity after hours. On the other hand, if you are backing
2980     up laptops that are only intermittently connected to the network you
2981     will want to have frequent wakeups (eg: hourly) to maximized the chance
2982     that each laptop is backed up.</p>
2983     </dd>
2984     <dd>
2985     <p>Examples:</p>
2986     </dd>
2987     <dd>
2988     <pre>
2989     <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A> = [22.5]; # once per day at 10:30 pm.
2990     <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A> = [1..23]; # every hour except midnight
2991     <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A> = [2,4,6,8,10,12,14,16,18,20,22]; # every 2 hours</pre>
2992     </dd>
2993     <dd>
2994     <p>The default value is every hour except midnight.</p>
2995     </dd>
2996     <dd>
2997     <p>The first entry of <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A> is when BackupPC_nightly
2998     is run. No other backups can run while BackupPC_nightly is
2999     running. You might want to re-arrange the entries in
3000     <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A> (they don't have to be ascending) so that
3001     the first entry is when you want BackupPC_nightly to run
3002     (eg: when you don't expect a lot of regular backups to run).</p>
3003     </dd>
3004     <p></p>
3005     <dt><strong><a name="item_%24conf%7bmaxbackups%7d">$Conf{MaxBackups} = 4;</a></strong><br />
3006     </dt>
3007     <dd>
3008     Maximum number of simultaneous backups to run. If there
3009     are no user backup requests then this is the maximum number
3010     of simultaneous backups.
3011     </dd>
3012     <p></p>
3013     <dt><strong><a name="item_%24conf%7bmaxuserbackups%7d">$Conf{MaxUserBackups} = 4;</a></strong><br />
3014     </dt>
3015     <dd>
3016     Additional number of simultaneous backups that users can run.
3017     As many as <a href="#item_%24conf%7bmaxbackups%7d">$Conf{MaxBackups}</A> + <a href="#item_%24conf%7bmaxuserbackups%7d">$Conf{MaxUserBackups}</A> requests can
3018     run at the same time.
3019     </dd>
3020     <p></p>
3021     <dt><strong><a name="item_%24conf%7bmaxpendingcmds%7d">$Conf{MaxPendingCmds} = 10;</a></strong><br />
3022     </dt>
3023     <dd>
3024     Maximum number of pending link commands. New backups will only be
3025     started if there are no more than <a href="#item_%24conf%7bmaxpendingcmds%7d">$Conf{MaxPendingCmds}</A> plus
3026     <a href="#item_%24conf%7bmaxbackups%7d">$Conf{MaxBackups}</A> number of pending link commands, plus running jobs.
3027     This limit is to make sure BackupPC doesn't fall too far behind in
3028     running BackupPC_link commands.
3029     </dd>
3030     <p></p>
3031     <dt><strong><a name="item_%24conf%7bmaxbackuppcnightlyjobs%7d">$Conf{MaxBackupPCNightlyJobs} = 2;</a></strong><br />
3032     </dt>
3033     <dd>
3034     How many BackupPC_nightly processes to run in parallel.
3035     </dd>
3036     <dd>
3037     <p>Each night, at the first wakeup listed in <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A>,
3038     BackupPC_nightly is run. Its job is to remove unneeded files
3039     in the pool, ie: files that only have one link. To avoid race
3040     conditions, BackupPC_nightly runs only when there are no backups
3041     running, and no backups will start while it runs.</p>
3042     </dd>
3043     <dd>
3044     <p>So to reduce the elapsed time, you might want to increase this
3045     setting to run several BackupPC_nightly processes in parallel
3046     (eg: 4, or even 8).</p>
3047     </dd>
3048     <p></p>
3049     <dt><strong><a name="item_%24conf%7bbackuppcnightlyperiod%7d">$Conf{BackupPCNightlyPeriod} = 1;</a></strong><br />
3050     </dt>
3051     <dd>
3052     How many days (runs) it takes BackupPC_nightly to traverse the
3053     entire pool. Normally this is 1, which means every night it runs,
3054     it does traverse the entire pool removing unused pool files.
3055     </dd>
3056     <dd>
3057     <p>Other valid values are 2, 4, 8, 16. This causes BackupPC_nightly to
3058     traverse 1/2, 1/4, 1/8 or 1/16th of the pool each night, meaning it
3059     takes 2, 4, 8 or 16 days to completely traverse the pool. The
3060     advantage is that each night the running time of BackupPC_nightly
3061     is reduced roughly in proportion, since the total job is split
3062     over multiple days. The disadvantage is that unused pool files
3063     take longer to get deleted, which will slightly increase disk
3064     usage.</p>
3065     </dd>
3066     <dd>
3067     <p>Note that even when <a href="#item_%24conf%7bbackuppcnightlyperiod%7d">$Conf{BackupPCNightlyPeriod}</A> &gt; 1, BackupPC_nightly
3068     still runs every night. It just does less work each time it runs.</p>
3069     </dd>
3070     <dd>
3071     <p>Examples:</p>
3072     </dd>
3073     <dd>
3074     <pre>
3075     <a href="#item_%24conf%7bbackuppcnightlyperiod%7d">$Conf{BackupPCNightlyPeriod}</A> = 1; # entire pool is checked every night</pre>
3076     </dd>
3077     <dd>
3078     <pre>
3079     <a href="#item_%24conf%7bbackuppcnightlyperiod%7d">$Conf{BackupPCNightlyPeriod}</A> = 2; # two days to complete pool check
3080     # (different half each night)</pre>
3081     </dd>
3082     <dd>
3083     <pre>
3084     <a href="#item_%24conf%7bbackuppcnightlyperiod%7d">$Conf{BackupPCNightlyPeriod}</A> = 4; # four days to complete pool check
3085     # (different quarter each night)</pre>
3086     </dd>
3087     <p></p>
3088     <dt><strong><a name="item_%24conf%7bmaxoldlogfiles%7d">$Conf{MaxOldLogFiles} = 14;</a></strong><br />
3089     </dt>
3090     <dd>
3091     Maximum number of log files we keep around in log directory.
3092     These files are aged nightly. A setting of 14 means the log
3093     directory will contain about 2 weeks of old log files, in
3094     particular at most the files LOG, LOG.0, LOG.1, ... LOG.13
3095     (except today's LOG, these files will have a .z extension if
3096     compression is on).
3097     </dd>
3098     <dd>
3099     <p>If you decrease this number after BackupPC has been running for a
3100     while you will have to manually remove the older log files.</p>
3101     </dd>
3102     <p></p>
3103     <dt><strong><a name="item_%24conf%7bdfpath%7d">$Conf{DfPath} = '/bin/df';</a></strong><br />
3104     </dt>
3105     <dd>
3106     Full path to the df command. Security caution: normal users
3107     should not allowed to write to this file or directory.
3108     </dd>
3109     <p></p>
3110     <dt><strong><a name="item_%24conf%7bdfcmd%7d">$Conf{DfCmd} = '$dfPath $topDir';</a></strong><br />
3111     </dt>
3112     <dd>
3113     Command to run df. The following variables are substituted at run-time:
3114     </dd>
3115     <dd>
3116     <pre>
3117     $dfPath path to df (<a href="#item_%24conf%7bdfpath%7d">$Conf{DfPath}</A>)
3118     $topDir top-level BackupPC data directory</pre>
3119     </dd>
3120     <p></p>
3121     <dt><strong><a name="item_%24conf%7bdfmaxusagepct%7d">$Conf{DfMaxUsagePct} = 95;</a></strong><br />
3122     </dt>
3123     <dd>
3124     Maximum threshold for disk utilization on the __TOPDIR__ filesystem.
3125     If the output from <a href="#item_%24conf%7bdfpath%7d">$Conf{DfPath}</A> reports a percentage larger than
3126     this number then no new regularly scheduled backups will be run.
3127     However, user requested backups (which are usually incremental and
3128     tend to be small) are still performed, independent of disk usage.
3129     Also, currently running backups will not be terminated when the disk
3130     usage exceeds this number.
3131     </dd>
3132     <p></p>
3133     <dt><strong><a name="item_%24conf%7btrashcleansleepsec%7d">$Conf{TrashCleanSleepSec} = 300;</a></strong><br />
3134     </dt>
3135     <dd>
3136     How long BackupPC_trashClean sleeps in seconds between each check
3137     of the trash directory. Once every 5 minutes should be reasonable.
3138     </dd>
3139     <p></p>
3140     <dt><strong><a name="item_%24conf%7bdhcpaddressranges%7d">$Conf{DHCPAddressRanges} = [];</a></strong><br />
3141     </dt>
3142     <dd>
3143     List of DHCP address ranges we search looking for PCs to backup.
3144     This is an array of hashes for each class C address range.
3145     This is only needed if hosts in the conf/hosts file have the
3146     dhcp flag set.
3147     </dd>
3148     <dd>
3149     <p>Examples:</p>
3150     </dd>
3151     <dd>
3152     <pre>
3153     # to specify 192.10.10.20 to 192.10.10.250 as the DHCP address pool
3154     <a href="#item_%24conf%7bdhcpaddressranges%7d">$Conf{DHCPAddressRanges}</A> = [
3155     {
3156     ipAddrBase =&gt; '192.10.10',
3157     first =&gt; 20,
3158     last =&gt; 250,
3159     },
3160     ];
3161     # to specify two pools (192.10.10.20-250 and 192.10.11.10-50)
3162     <a href="#item_%24conf%7bdhcpaddressranges%7d">$Conf{DHCPAddressRanges}</A> = [
3163     {
3164     ipAddrBase =&gt; '192.10.10',
3165     first =&gt; 20,
3166     last =&gt; 250,
3167     },
3168     {
3169     ipAddrBase =&gt; '192.10.11',
3170     first =&gt; 10,
3171     last =&gt; 50,
3172     },
3173     ];</pre>
3174     </dd>
3175     <p></p>
3176     <dt><strong><a name="item_%24conf%7bbackuppcuser%7d">$Conf{BackupPCUser} = '';</a></strong><br />
3177     </dt>
3178     <dt><strong><a name="item_%24conf%7bcgidir%7d">$Conf{CgiDir} = '';</a></strong><br />
3179     </dt>
3180     <dt><strong><a name="item_%24conf%7binstalldir%7d">$Conf{InstallDir} = '';</a></strong><br />
3181     </dt>
3182     <dd>
3183     These configuration settings aren't used by BackupPC, but simply
3184     remember a few settings used by configure.pl during installation.
3185     These are used by configure.pl when upgrading to new versions of
3186     BackupPC.
3187     </dd>
3188     <p></p>
3189     <dt><strong><a name="item_%24conf%7bbackuppcuserverify%7d">$Conf{BackupPCUserVerify} = 1;</a></strong><br />
3190     </dt>
3191     <dd>
3192     Whether BackupPC and the CGI script BackupPC_Admin verify that they
3193     are really running as user <a href="#item_%24conf%7bbackuppcuser%7d">$Conf{BackupPCUser}</A>. If this flag is set
3194     and the effective user id (euid) differs from <a href="#item_%24conf%7bbackuppcuser%7d">$Conf{BackupPCUser}</A>
3195     then both scripts exit with an error. This catches cases where
3196     BackupPC might be accidently started as root or the wrong user,
3197     or if the CGI script is not installed correctly.
3198     </dd>
3199     <p></p>
3200     <dt><strong><a name="item_%24conf%7bhardlinkmax%7d">$Conf{HardLinkMax} = 31999;</a></strong><br />
3201     </dt>
3202     <dd>
3203     Maximum number of hardlinks supported by the $TopDir file system
3204     that BackupPC uses. Most linux or unix file systems should support
3205     at least 32000 hardlinks per file, or 64000 in other cases. If a pool
3206     file already has this number of hardlinks, a new pool file is created
3207     so that new hardlinks can be accommodated. This limit will only
3208     be hit if an identical file appears at least this number of times
3209     across all the backups.
3210     </dd>
3211     <p></p></dl>
3212     <p>
3213     </p>
3214     <h2><a name="what_to_backup_and_when_to_do_it">What to backup and when to do it</a></h2>
3215     <dl>
3216     <dt><strong><a name="item_%24conf%7bsmbsharename%7d">$Conf{SmbShareName} = 'C$';</a></strong><br />
3217     </dt>
3218     <dd>
3219     Name of the host share that is backed up when using SMB. This can be a
3220     string or an array of strings if there are multiple shares per host.
3221     Examples:
3222     </dd>
3223     <dd>
3224     <pre>
3225     <a href="#item_%24conf%7bsmbsharename%7d">$Conf{SmbShareName}</A> = 'c'; # backup 'c' share
3226     <a href="#item_%24conf%7bsmbsharename%7d">$Conf{SmbShareName}</A> = ['c', 'd']; # backup 'c' and 'd' shares</pre>
3227     </dd>
3228     <dd>
3229     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'smb'.</p>
3230     </dd>
3231     <p></p>
3232     <dt><strong><a name="item_%24conf%7bsmbshareusername%7d">$Conf{SmbShareUserName} = '';</a></strong><br />
3233     </dt>
3234     <dd>
3235     Smbclient share user name. This is passed to smbclient's -U argument.
3236     </dd>
3237     <dd>
3238     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'smb'.</p>
3239     </dd>
3240     <p></p>
3241     <dt><strong><a name="item_%24conf%7bsmbsharepasswd%7d">$Conf{SmbSharePasswd} = '';</a></strong><br />
3242     </dt>
3243     <dd>
3244     Smbclient share password. This is passed to smbclient via its PASSWD
3245     environment variable. There are several ways you can tell BackupPC
3246     the smb share password. In each case you should be very careful about
3247     security. If you put the password here, make sure that this file is
3248     not readable by regular users! See the ``Setting up config.pl'' section
3249     in the documentation for more information.
3250     </dd>
3251     <dd>
3252     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'smb'.</p>
3253     </dd>
3254     <p></p>
3255     <dt><strong><a name="item_%24conf%7btarsharename%7d">$Conf{TarShareName} = '/';</a></strong><br />
3256     </dt>
3257     <dd>
3258     Which host directories to backup when using tar transport. This can be a
3259     string or an array of strings if there are multiple directories to
3260     backup per host. Examples:
3261     </dd>
3262     <dd>
3263     <pre>
3264     <a href="#item_%24conf%7btarsharename%7d">$Conf{TarShareName}</A> = '/'; # backup everything
3265     <a href="#item_%24conf%7btarsharename%7d">$Conf{TarShareName}</A> = '/home'; # only backup /home
3266     <a href="#item_%24conf%7btarsharename%7d">$Conf{TarShareName}</A> = ['/home', '/src']; # backup /home and /src</pre>
3267     </dd>
3268     <dd>
3269     <p>The fact this parameter is called 'TarShareName' is for historical
3270     consistency with the Smb transport options. You can use any valid
3271     directory on the client: there is no need for it to correspond to
3272     any Smb share or device mount point.</p>
3273     </dd>
3274     <dd>
3275     <p>Note also that you can also use <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A> to specify
3276     a specific list of directories to backup. It's more efficient to
3277     use this option instead of <a href="#item_%24conf%7btarsharename%7d">$Conf{TarShareName}</A> since a new tar is
3278     run for each entry in <a href="#item_%24conf%7btarsharename%7d">$Conf{TarShareName}</A>.</p>
3279     </dd>
3280     <dd>
3281     <p>On the other hand, if you add --one-file-system to <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A>
3282     you can backup each file system separately, which makes restoring one
3283     bad file system easier. In this case you would list all of the mount
3284     points here, since you can't get the same result with
3285     <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A>:</p>
3286     </dd>
3287     <dd>
3288     <pre>
3289     <a href="#item_%24conf%7btarsharename%7d">$Conf{TarShareName}</A> = ['/', '/var', '/data', '/boot'];</pre>
3290     </dd>
3291     <dd>
3292     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'tar'.</p>
3293     </dd>
3294     <p></p>
3295     <dt><strong><a name="item_%24conf%7bfullperiod%7d">$Conf{FullPeriod} = 6.97;</a></strong><br />
3296     </dt>
3297     <dd>
3298     Minimum period in days between full backups. A full dump will only be
3299     done if at least this much time has elapsed since the last full dump,
3300     and at least <a href="#item_%24conf%7bincrperiod%7d">$Conf{IncrPeriod}</A> days has elapsed since the last
3301     successful dump.
3302     </dd>
3303     <dd>
3304     <p>Typically this is set slightly less than an integer number of days. The
3305     time taken for the backup, plus the granularity of <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A>
3306     will make the actual backup interval a bit longer.</p>
3307     </dd>
3308     <dd>
3309     <p>There are two special values for <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>:</p>
3310     </dd>
3311     <dd>
3312     <pre>
3313     -1 Don't do any regular backups on this machine. Manually
3314     requested backups (via the CGI interface) will still occur.</pre>
3315     </dd>
3316     <dd>
3317     <pre>
3318     -2 Don't do any backups on this machine. Manually requested
3319     backups (via the CGI interface) will be ignored.</pre>
3320     </dd>
3321     <dd>
3322     <p>These special settings are useful for a client that is no longer
3323     being backed up (eg: a retired machine), but you wish to keep the
3324     last backups available for browsing or restoring to other machines.</p>
3325     </dd>
3326     <p></p>
3327     <dt><strong><a name="item_%24conf%7bincrperiod%7d">$Conf{IncrPeriod} = 0.97;</a></strong><br />
3328     </dt>
3329     <dd>
3330     Minimum period in days between incremental backups (a user requested
3331     incremental backup will be done anytime on demand).
3332     </dd>
3333     <dd>
3334     <p>Typically this is set slightly less than an integer number of days. The
3335     time taken for the backup, plus the granularity of <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A>
3336     will make the actual backup interval a bit longer.</p>
3337     </dd>
3338     <p></p>
3339     <dt><strong><a name="item_%24conf%7bfullkeepcnt%7d">$Conf{FullKeepCnt} = 1;</a></strong><br />
3340     </dt>
3341     <dd>
3342     Number of full backups to keep. Must be &gt;= 1.
3343     </dd>
3344     <dd>
3345     <p>In the steady state, each time a full backup completes successfully
3346     the oldest one is removed. If this number is decreased, the
3347     extra old backups will be removed.</p>
3348     </dd>
3349     <dd>
3350     <p>If filling of incremental dumps is off the oldest backup always
3351     has to be a full (ie: filled) dump. This might mean one or two
3352     extra full dumps are kept until the oldest incremental backups expire.</p>
3353     </dd>
3354     <dd>
3355     <p>Exponential backup expiry is also supported. This allows you to specify:</p>
3356     </dd>
3357     <dd>
3358     <pre>
3359     - num fulls to keep at intervals of 1 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>, followed by
3360     - num fulls to keep at intervals of 2 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>,
3361     - num fulls to keep at intervals of 4 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>,
3362     - num fulls to keep at intervals of 8 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>,
3363     - num fulls to keep at intervals of 16 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>,</pre>
3364     </dd>
3365     <dd>
3366     <p>and so on. This works by deleting every other full as each expiry
3367     boundary is crossed.</p>
3368     </dd>
3369     <dd>
3370     <p>Exponential expiry is specified using an array for <a href="#item_%24conf%7bfullkeepcnt%7d">$Conf{FullKeepCnt}</A>:</p>
3371     </dd>
3372     <dd>
3373     <pre>
3374     <a href="#item_%24conf%7bfullkeepcnt%7d">$Conf{FullKeepCnt}</A> = [4, 2, 3];</pre>
3375     </dd>
3376     <dd>
3377     <p>Entry #n specifies how many fulls to keep at an interval of
3378     2^n * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A> (ie: 1, 2, 4, 8, 16, 32, ...).</p>
3379     </dd>
3380     <dd>
3381     <p>The example above specifies keeping 4 of the most recent full backups
3382     (1 week interval) two full backups at 2 week intervals, and 3 full
3383     backups at 4 week intervals, eg:</p>
3384     </dd>
3385     <dd>
3386     <pre>
3387     full 0 19 weeks old \
3388     full 1 15 weeks old &gt;--- 3 backups at 4 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>
3389     full 2 11 weeks old /
3390     full 3 7 weeks old \____ 2 backups at 2 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>
3391     full 4 5 weeks old /
3392     full 5 3 weeks old \
3393     full 6 2 weeks old \___ 4 backups at 1 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>
3394     full 7 1 week old /
3395     full 8 current /</pre>
3396     </dd>
3397     <dd>
3398     <p>On a given week the spacing might be less than shown as each backup
3399     ages through each expiry period. For example, one week later, a
3400     new full is completed and the oldest is deleted, giving:</p>
3401     </dd>
3402     <dd>
3403     <pre>
3404     full 0 16 weeks old \
3405     full 1 12 weeks old &gt;--- 3 backups at 4 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>
3406     full 2 8 weeks old /
3407     full 3 6 weeks old \____ 2 backups at 2 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>
3408     full 4 4 weeks old /
3409     full 5 3 weeks old \
3410     full 6 2 weeks old \___ 4 backups at 1 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>
3411     full 7 1 week old /
3412     full 8 current /</pre>
3413     </dd>
3414     <dd>
3415     <p>You can specify 0 as a count (except in the first entry), and the
3416     array can be as long as you wish. For example:</p>
3417     </dd>
3418     <dd>
3419     <pre>
3420     <a href="#item_%24conf%7bfullkeepcnt%7d">$Conf{FullKeepCnt}</A> = [4, 0, 4, 0, 0, 2];</pre>
3421     </dd>
3422     <dd>
3423     <p>This will keep 10 full dumps, 4 most recent at 1 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A>,
3424     followed by 4 at an interval of 4 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A> (approx 1 month
3425     apart), and then 2 at an interval of 32 * <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A> (approx
3426     7-8 months apart).</p>
3427     </dd>
3428     <dd>
3429     <p>Example: these two settings are equivalent and both keep just
3430     the four most recent full dumps:</p>
3431     </dd>
3432     <dd>
3433     <pre>
3434     <a href="#item_%24conf%7bfullkeepcnt%7d">$Conf{FullKeepCnt}</A> = 4;
3435     <a href="#item_%24conf%7bfullkeepcnt%7d">$Conf{FullKeepCnt}</A> = [4];</pre>
3436     </dd>
3437     <p></p>
3438     <dt><strong><a name="item_%24conf%7bfullkeepcntmin%7d">$Conf{FullKeepCntMin} = 1;</a></strong><br />
3439     </dt>
3440     <dt><strong><a name="item_%24conf%7bfullagemax%7d">$Conf{FullAgeMax} = 90;</a></strong><br />
3441     </dt>
3442     <dd>
3443     Very old full backups are removed after <a href="#item_%24conf%7bfullagemax%7d">$Conf{FullAgeMax}</A> days. However,
3444     we keep at least <a href="#item_%24conf%7bfullkeepcntmin%7d">$Conf{FullKeepCntMin}</A> full backups no matter how old
3445     they are.
3446     </dd>
3447     <dd>
3448     <p>Note that <a href="#item_%24conf%7bfullagemax%7d">$Conf{FullAgeMax}</A> will be increased to <a href="#item_%24conf%7bfullagemax%7d">$Conf{FullAgeMax}</A>
3449     times <a href="#item_%24conf%7bfullperiod%7d">$Conf{FullPeriod}</A> if <a href="#item_%24conf%7bfullagemax%7d">$Conf{FullAgeMax}</A> specifies enough
3450     full backups to exceed <a href="#item_%24conf%7bfullagemax%7d">$Conf{FullAgeMax}</A>.</p>
3451     </dd>
3452     <p></p>
3453     <dt><strong><a name="item_%24conf%7bincrkeepcnt%7d">$Conf{IncrKeepCnt} = 6;</a></strong><br />
3454     </dt>
3455     <dd>
3456     Number of incremental backups to keep. Must be &gt;= 1.
3457     </dd>
3458     <dd>
3459     <p>In the steady state, each time an incr backup completes successfully
3460     the oldest one is removed. If this number is decreased, the
3461     extra old backups will be removed.</p>
3462     </dd>
3463     <p></p>
3464     <dt><strong><a name="item_%24conf%7bincrkeepcntmin%7d">$Conf{IncrKeepCntMin} = 1;</a></strong><br />
3465     </dt>
3466     <dt><strong><a name="item_%24conf%7bincragemax%7d">$Conf{IncrAgeMax} = 30;</a></strong><br />
3467     </dt>
3468     <dd>
3469     Very old incremental backups are removed after <a href="#item_%24conf%7bincragemax%7d">$Conf{IncrAgeMax}</A> days.
3470     However, we keep at least <a href="#item_%24conf%7bincrkeepcntmin%7d">$Conf{IncrKeepCntMin}</A> incremental backups no
3471     matter how old they are.
3472     </dd>
3473     <p></p>
3474     <dt><strong><a name="item_%24conf%7bpartialagemax%7d">$Conf{PartialAgeMax} = 3;</a></strong><br />
3475     </dt>
3476     <dd>
3477     A failed full backup is saved as a partial backup. The rsync
3478     XferMethod can take advantage of the partial full when the next
3479     backup is run. This parameter sets the age of the partial full
3480     in days: if the partial backup is older than this number of
3481     days, then rsync will ignore (not use) the partial full when
3482     the next backup is run. If you set this to a negative value
3483     then no partials will be saved. If you set this to 0, partials
3484     will be saved, but will not be used by the next backup.
3485     </dd>
3486     <dd>
3487     <p>The default setting of 3 days means that a partial older than
3488     3 days is ignored when the next full backup is done.</p>
3489     </dd>
3490     <p></p>
3491     <dt><strong><a name="item_%24conf%7bincrfill%7d">$Conf{IncrFill} = 0;</a></strong><br />
3492     </dt>
3493     <dd>
3494     Whether incremental backups are filled. ``Filling'' means that the
3495     most recent full (or filled) dump is merged into the new incremental
3496     dump using hardlinks. This makes an incremental dump look like a
3497     full dump. Prior to v1.03 all incremental backups were filled.
3498     In v1.4.0 and later the default is off.
3499     </dd>
3500     <dd>
3501     <p>BackupPC, and the cgi interface in particular, do the right thing on
3502     un-filled incremental backups. It will correctly display the merged
3503     incremental backup with the most recent filled backup, giving the
3504     un-filled incremental backups a filled appearance. That means it
3505     invisible to the user whether incremental dumps are filled or not.</p>
3506     </dd>
3507     <dd>
3508     <p>Filling backups takes a little extra disk space, and it does cost
3509     some extra disk activity for filling, and later removal. Filling
3510     is no longer useful, since file mangling and compression doesn't
3511     make a filled backup very useful. It's likely the filling option
3512     will be removed from future versions: filling will be delegated to
3513     the display and extraction of backup data.</p>
3514     </dd>
3515     <dd>
3516     <p>If filling is off, BackupPC makes sure that the oldest backup is
3517     a full, otherwise the following incremental backups will be
3518     incomplete. This might mean an extra full backup has to be
3519     kept until the following incremental backups expire.</p>
3520     </dd>
3521     <dd>
3522     <p>The default is off. You can turn this on or off at any
3523     time without affecting existing backups.</p>
3524     </dd>
3525     <p></p>
3526     <dt><strong><a name="item_%24conf%7brestoreinfokeepcnt%7d">$Conf{RestoreInfoKeepCnt} = 10;</a></strong><br />
3527     </dt>
3528     <dd>
3529     Number of restore logs to keep. BackupPC remembers information about
3530     each restore request. This number per client will be kept around before
3531     the oldest ones are pruned.
3532     </dd>
3533     <dd>
3534     <p>Note: files/dirs delivered via Zip or Tar downloads don't count as
3535     restores. Only the first restore option (where the files and dirs
3536     are written to the host) count as restores that are logged.</p>
3537     </dd>
3538     <p></p>
3539     <dt><strong><a name="item_%24conf%7barchiveinfokeepcnt%7d">$Conf{ArchiveInfoKeepCnt} = 10;</a></strong><br />
3540     </dt>
3541     <dd>
3542     Number of archive logs to keep. BackupPC remembers information
3543     about each archive request. This number per archive client will
3544     be kept around before the oldest ones are pruned.
3545     </dd>
3546     <p></p>
3547     <dt><strong><a name="item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly} = undef;</a></strong><br />
3548     </dt>
3549     <dd>
3550     List of directories or files to backup. If this is defined, only these
3551     directories or files will be backed up.
3552     </dd>
3553     <dd>
3554     <p>For Smb, only one of <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> and <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A>
3555     can be specified per share. If both are set for a particular share, then
3556     <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A> takes precedence and <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A>
3557     is ignored.</p>
3558     </dd>
3559     <dd>
3560     <p>This can be set to a string, an array of strings, or, in the case
3561     of multiple shares, a hash of strings or arrays. A hash is used
3562     to give a list of directories or files to backup for each share
3563     (the share name is the key). If this is set to just a string or
3564     array, and <a href="#item_%24conf%7bsmbsharename%7d">$Conf{SmbShareName}</A> contains multiple share names, then
3565     the setting is assumed to apply all shares.</p>
3566     </dd>
3567     <dd>
3568     <p>Examples:</p>
3569     </dd>
3570     <dd>
3571     <pre>
3572     <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A> = '/myFiles';
3573     <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A> = ['/myFiles']; # same as first example
3574     <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A> = ['/myFiles', '/important'];
3575     <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A> = {
3576     'c' =&gt; ['/myFiles', '/important'], # these are for 'c' share
3577     'd' =&gt; ['/moreFiles', '/archive'], # these are for 'd' share
3578     };</pre>
3579     </dd>
3580     <p></p>
3581     <dt><strong><a name="item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude} = undef;</a></strong><br />
3582     </dt>
3583     <dd>
3584     List of directories or files to exclude from the backup. For Smb,
3585     only one of <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> and <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A>
3586     can be specified per share. If both are set for a particular share,
3587     then <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A> takes precedence and
3588     <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> is ignored.
3589     </dd>
3590     <dd>
3591     <p>This can be set to a string, an array of strings, or, in the case
3592     of multiple shares, a hash of strings or arrays. A hash is used
3593     to give a list of directories or files to exclude for each share
3594     (the share name is the key). If this is set to just a string or
3595     array, and <a href="#item_%24conf%7bsmbsharename%7d">$Conf{SmbShareName}</A> contains multiple share names, then
3596     the setting is assumed to apply to all shares.</p>
3597     </dd>
3598     <dd>
3599     <p>The exact behavior is determined by the underlying transport program,
3600     smbclient or tar. For smbclient the exlclude file list is passed into
3601     the X option. Simple shell wild-cards using ``*'' or ``?'' are allowed.</p>
3602     </dd>
3603     <dd>
3604     <p>For tar, if the exclude file contains a ``/'' it is assumed to be anchored
3605     at the start of the string. Since all the tar paths start with ``./'',
3606     BackupPC prepends a ``.'' if the exclude file starts with a ``/''. Note
3607     that GNU tar version &gt;= 1.13.7 is required for the exclude option to
3608     work correctly. For linux or unix machines you should add
3609     ``/proc'' to <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> unless you have specified
3610     --one-file-system in <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A> or --one-file-system in
3611     <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A>. Also, for tar, do not use a trailing ``/'' in
3612     the directory name: a trailing ``/'' causes the name to not match
3613     and the directory will not be excluded.</p>
3614     </dd>
3615     <dd>
3616     <p>Users report that for smbclient you should specify a directory
3617     followed by ``/*'', eg: ``/proc/*'', instead of just ``/proc''.</p>
3618     </dd>
3619     <dd>
3620     <p>Examples:</p>
3621     </dd>
3622     <dd>
3623     <pre>
3624     <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> = '/temp';
3625     <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> = ['/temp']; # same as first example
3626     <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> = ['/temp', '/winnt/tmp'];
3627     <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> = {
3628     'c' =&gt; ['/temp', '/winnt/tmp'], # these are for 'c' share
3629     'd' =&gt; ['/junk', '/dont_back_this_up'], # these are for 'd' share
3630     };</pre>
3631     </dd>
3632     <p></p>
3633     <dt><strong><a name="item_%24conf%7bblackoutbadpinglimit%7d">$Conf{BlackoutBadPingLimit} = 3;</a></strong><br />
3634     </dt>
3635     <dt><strong><a name="item_%24conf%7bblackoutgoodcnt%7d">$Conf{BlackoutGoodCnt} = 7;</a></strong><br />
3636     </dt>
3637     <dd>
3638     PCs that are always or often on the network can be backed up after
3639     hours, to reduce PC, network and server load during working hours. For
3640     each PC a count of consecutive good pings is maintained. Once a PC has
3641     at least <a href="#item_%24conf%7bblackoutgoodcnt%7d">$Conf{BlackoutGoodCnt}</A> consecutive good pings it is subject
3642     to ``blackout'' and not backed up during hours and days specified by
3643     <a href="#item_%24conf%7bblackoutperiods%7d">$Conf{BlackoutPeriods}</A>.
3644     </dd>
3645     <dd>
3646     <p>To allow for periodic rebooting of a PC or other brief periods when a
3647     PC is not on the network, a number of consecutive bad pings is allowed
3648     before the good ping count is reset. This parameter is
3649     <a href="#item_%24conf%7bblackoutbadpinglimit%7d">$Conf{BlackoutBadPingLimit}</A>.</p>
3650     </dd>
3651     <dd>
3652     <p>Note that bad and good pings don't occur with the same interval. If a
3653     machine is always on the network, it will only be pinged roughly once
3654     every <a href="#item_%24conf%7bincrperiod%7d">$Conf{IncrPeriod}</A> (eg: once per day). So a setting for
3655     <a href="#item_%24conf%7bblackoutgoodcnt%7d">$Conf{BlackoutGoodCnt}</A> of 7 means it will take around 7 days for a
3656     machine to be subject to blackout. On the other hand, if a ping is
3657     failed, it will be retried roughly every time BackupPC wakes up, eg,
3658     every one or two hours. So a setting for <a href="#item_%24conf%7bblackoutbadpinglimit%7d">$Conf{BlackoutBadPingLimit}</A> of
3659     3 means that the PC will lose its blackout status after 3-6 hours of
3660     unavailability.</p>
3661     </dd>
3662     <dd>
3663     <p>To disable the blackout feature set <a href="#item_%24conf%7bblackoutgoodcnt%7d">$Conf{BlackoutGoodCnt}</A> to a negative
3664     value. A value of 0 will make all machines subject to blackout. But
3665     if you don't want to do any backups during the day it would be easier
3666     to just set <a href="#item_%24conf%7bwakeupschedule%7d">$Conf{WakeupSchedule}</A> to a restricted schedule.</p>
3667     </dd>
3668     <p></p>
3669     <dt><strong><a name="item_%24conf%7bblackoutperiods%7d">$Conf{BlackoutPeriods} = [ ... ];</a></strong><br />
3670     </dt>
3671     <dd>
3672     One or more blackout periods can be specified. If a client is
3673     subject to blackout then no regular (non-manual) backups will
3674     be started during any of these periods. hourBegin and hourEnd
3675     specify hours fro midnight and weekDays is a list of days of
3676     the week where 0 is Sunday, 1 is Monday etc.
3677     </dd>
3678     <dd>
3679     <p>For example:</p>
3680     </dd>
3681     <dd>
3682     <pre>
3683     <a href="#item_%24conf%7bblackoutperiods%7d">$Conf{BlackoutPeriods}</A> = [
3684     {
3685     hourBegin =&gt; 7.0,
3686     hourEnd =&gt; 19.5,
3687     weekDays =&gt; [1, 2, 3, 4, 5],
3688     },
3689     ];</pre>
3690     </dd>
3691     <dd>
3692     <p>specifies one blackout period from 7:00am to 7:30pm local time
3693     on Mon-Fri.</p>
3694     </dd>
3695     <dd>
3696     <p>The blackout period can also span midnight by setting
3697     hourBegin &gt; hourEnd, eg:</p>
3698     </dd>
3699     <dd>
3700     <pre>
3701     <a href="#item_%24conf%7bblackoutperiods%7d">$Conf{BlackoutPeriods}</A> = [
3702     {
3703     hourBegin =&gt; 7.0,
3704     hourEnd =&gt; 19.5,
3705     weekDays =&gt; [1, 2, 3, 4, 5],
3706     },
3707     {
3708     hourBegin =&gt; 23,
3709     hourEnd =&gt; 5,
3710     weekDays =&gt; [5, 6],
3711     },
3712     ];</pre>
3713     </dd>
3714     <dd>
3715     <p>This specifies one blackout period from 7:00am to 7:30pm local time
3716     on Mon-Fri, and a second period from 11pm to 5am on Friday and
3717     Saturday night.</p>
3718     </dd>
3719     <p></p>
3720     <dt><strong><a name="item_%24conf%7bbackupzerofilesisfatal%7d">$Conf{BackupZeroFilesIsFatal} = 1;</a></strong><br />
3721     </dt>
3722     <dd>
3723     A backup of a share that has zero files is considered fatal. This is
3724     used to catch miscellaneous Xfer errors that result in no files being
3725     backed up. If you have shares that might be empty (and therefore an
3726     empty backup is valid) you should set this flag to 0.
3727     </dd>
3728     <p></p></dl>
3729     <p>
3730     </p>
3731     <h2><a name="general_perpc_configuration_settings">General per-PC configuration settings</a></h2>
3732     <dl>
3733     <dt><strong><a name="item_%24conf%7bxfermethod%7d">$Conf{XferMethod} = 'smb';</a></strong><br />
3734     </dt>
3735     <dd>
3736     What transport method to use to backup each host. If you have
3737     a mixed set of WinXX and linux/unix hosts you will need to override
3738     this in the per-PC config.pl.
3739     </dd>
3740     <dd>
3741     <p>The valid values are:</p>
3742     </dd>
3743     <dd>
3744     <pre>
3745     - 'smb': backup and restore via smbclient and the SMB protocol.
3746     Easiest choice for WinXX.</pre>
3747     </dd>
3748     <dd>
3749     <pre>
3750     - 'rsync': backup and restore via rsync (via rsh or ssh).
3751     Best choice for linux/unix. Good choice also for WinXX.</pre>
3752     </dd>
3753     <dd>
3754     <pre>
3755     - 'rsyncd': backup and restre via rsync daemon on the client.
3756     Best choice for linux/unix if you have rsyncd running on
3757     the client. Good choice also for WinXX.</pre>
3758     </dd>
3759     <dd>
3760     <pre>
3761     - 'tar': backup and restore via tar, tar over ssh, rsh or nfs.
3762     Good choice for linux/unix.</pre>
3763     </dd>
3764     <dd>
3765     <pre>
3766     - 'archive': host is a special archive host. Backups are not done.
3767     An archive host is used to archive other host's backups
3768     to permanent media, such as tape, CDR or DVD.</pre>
3769     </dd>
3770     <p></p>
3771     <dt><strong><a name="item_%24conf%7bxferloglevel%7d">$Conf{XferLogLevel} = 1;</a></strong><br />
3772     </dt>
3773     <dd>
3774     Level of verbosity in Xfer log files. 0 means be quiet, 1 will give
3775     will give one line per file, 2 will also show skipped files on
3776     incrementals, higher values give more output.
3777     </dd>
3778     <p></p>
3779     <dt><strong><a name="item_%24conf%7bsmbclientpath%7d">$Conf{SmbClientPath} = '/usr/bin/smbclient';</a></strong><br />
3780     </dt>
3781     <dd>
3782     Full path for smbclient. Security caution: normal users should not
3783     allowed to write to this file or directory.
3784     </dd>
3785     <dd>
3786     <p>smbclient is from the Samba distribution. smbclient is used to
3787     actually extract the incremental or full dump of the share filesystem
3788     from the PC.</p>
3789     </dd>
3790     <dd>
3791     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'smb'.</p>
3792     </dd>
3793     <p></p>
3794     <dt><strong><a name="item_%24conf%7bsmbclientfullcmd%7d">$Conf{SmbClientFullCmd} = '$smbClientPath \\\\$host\\$shareName' ...</a></strong><br />
3795     </dt>
3796     <dd>
3797     Command to run smbclient for a full dump.
3798     This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'smb'.
3799     </dd>
3800     <dd>
3801     <p>The following variables are substituted at run-time:</p>
3802     </dd>
3803     <dd>
3804     <pre>
3805     $smbClientPath same as <a href="#item_%24conf%7bsmbclientpath%7d">$Conf{SmbClientPath}</A>
3806     $host host to backup/restore
3807     $hostIP host IP address
3808     $shareName share name
3809     $userName user name
3810     $fileList list of files to backup (based on exclude/include)
3811     $I_option optional -I option to smbclient
3812     $X_option exclude option (if $fileList is an exclude list)
3813     $timeStampFile start time for incremental dump</pre>
3814     </dd>
3815     <p></p>
3816     <dt><strong><a name="item_%24conf%7bsmbclientincrcmd%7d">$Conf{SmbClientIncrCmd} = '$smbClientPath \\\\$host\\$shareName' ...</a></strong><br />
3817     </dt>
3818     <dd>
3819     Command to run smbclient for an incremental dump.
3820     This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'smb'.
3821     </dd>
3822     <dd>
3823     <p>Same variable substitutions are applied as <a href="#item_%24conf%7bsmbclientfullcmd%7d">$Conf{SmbClientFullCmd}</A>.</p>
3824     </dd>
3825     <p></p>
3826     <dt><strong><a name="item_%24conf%7bsmbclientrestorecmd%7d">$Conf{SmbClientRestoreCmd} = '$smbClientPath \\\\$host\\$shareName' ...</a></strong><br />
3827     </dt>
3828     <dd>
3829     Command to run smbclient for a restore.
3830     This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'smb'.
3831     </dd>
3832     <dd>
3833     <p>Same variable substitutions are applied as <a href="#item_%24conf%7bsmbclientfullcmd%7d">$Conf{SmbClientFullCmd}</A>.</p>
3834     </dd>
3835     <dd>
3836     <p>If your smb share is read-only then direct restores will fail.
3837     You should set <a href="#item_%24conf%7bsmbclientrestorecmd%7d">$Conf{SmbClientRestoreCmd}</A> to undef and the
3838     corresponding CGI restore option will be removed.</p>
3839     </dd>
3840     <p></p>
3841     <dt><strong><a name="item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd} = '$sshPath -q -x -n -l root $host' ...</a></strong><br />
3842     </dt>
3843     <dd>
3844     Full command to run tar on the client. GNU tar is required. You will
3845     need to fill in the correct paths for ssh2 on the local host (server)
3846     and GNU tar on the client. Security caution: normal users should not
3847     allowed to write to these executable files or directories.
3848     </dd>
3849     <dd>
3850     <p>See the documentation for more information about setting up ssh2 keys.</p>
3851     </dd>
3852     <dd>
3853     <p>If you plan to use NFS then tar just runs locally and ssh2 is not needed.
3854     For example, assuming the client filesystem is mounted below /mnt/hostName,
3855     you could use something like:</p>
3856     </dd>
3857     <dd>
3858     <pre>
3859     <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A> = '$tarPath -c -v -f - -C /mnt/$host/$shareName'
3860     . ' --totals';</pre>
3861     </dd>
3862     <dd>
3863     <p>In the case of NFS or rsh you need to make sure BackupPC's privileges
3864     are sufficient to read all the files you want to backup. Also, you
3865     will probably want to add ``/proc'' to <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A>.</p>
3866     </dd>
3867     <dd>
3868     <p>The following variables are substituted at run-time:</p>
3869     </dd>
3870     <dd>
3871     <pre>
3872     $host host name
3873     $hostIP host's IP address
3874     $incrDate newer-than date for incremental backups
3875     $shareName share name to backup (ie: top-level directory path)
3876     $fileList specific files to backup or exclude
3877     $tarPath same as <a href="#item_%24conf%7btarclientpath%7d">$Conf{TarClientPath}</A>
3878     $sshPath same as <a href="#item_%24conf%7bsshpath%7d">$Conf{SshPath}</A></pre>
3879     </dd>
3880     <dd>
3881     <p>If a variable is followed by a ``+'' it is shell escaped. This is
3882     necessary for the command part of ssh or rsh, since it ends up
3883     getting passed through the shell.</p>
3884     </dd>
3885     <dd>
3886     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'tar'.</p>
3887     </dd>
3888     <p></p>
3889     <dt><strong><a name="item_%24conf%7btarfullargs%7d">$Conf{TarFullArgs} = '$fileList+';</a></strong><br />
3890     </dt>
3891     <dd>
3892     Extra tar arguments for full backups. Several variables are substituted at
3893     run-time. See <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A> for the list of variable substitutions.
3894     </dd>
3895     <dd>
3896     <p>If you are running tar locally (ie: without rsh or ssh) then remove the
3897     ``+'' so that the argument is no longer shell escaped.</p>
3898     </dd>
3899     <dd>
3900     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'tar'.</p>
3901     </dd>
3902     <p></p>
3903     <dt><strong><a name="item_%24conf%7btarincrargs%7d">$Conf{TarIncrArgs} = '--newer=$incrDate+ $fileList+';</a></strong><br />
3904     </dt>
3905     <dd>
3906     Extra tar arguments for incr backups. Several variables are substituted at
3907     run-time. See <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A> for the list of variable substitutions.
3908     </dd>
3909     <dd>
3910     <p>Note that GNU tar has several methods for specifying incremental backups,
3911     including:</p>
3912     </dd>
3913     <dd>
3914     <pre>
3915     --newer-mtime $incrDate+
3916     This causes a file to be included if the modification time is
3917     later than $incrDate (meaning its contents might have changed).
3918     But changes in the ownership or modes will not qualify the
3919     file to be included in an incremental.</pre>
3920     </dd>
3921     <dd>
3922     <pre>
3923     --newer=$incrDate+
3924     This causes the file to be included if any attribute of the
3925     file is later than $incrDate, meaning either attributes or
3926     the modification time. This is the default method. Do
3927     not use --atime-preserve in <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A> above,
3928     otherwise resetting the atime (access time) counts as an
3929     attribute change, meaning the file will always be included
3930     in each new incremental dump.</pre>
3931     </dd>
3932     <dd>
3933     <p>If you are running tar locally (ie: without rsh or ssh) then remove the
3934     ``+'' so that the argument is no longer shell escaped.</p>
3935     </dd>
3936     <dd>
3937     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'tar'.</p>
3938     </dd>
3939     <p></p>
3940     <dt><strong><a name="item_%24conf%7btarclientrestorecmd%7d">$Conf{TarClientRestoreCmd} = '$sshPath -q -x -l root $host' ...</a></strong><br />
3941     </dt>
3942     <dd>
3943     Full command to run tar for restore on the client. GNU tar is required.
3944     This can be the same as <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A>, with tar's -c replaced by -x
3945     and ssh's -n removed.
3946     </dd>
3947     <dd>
3948     <p>See <a href="#item_%24conf%7btarclientcmd%7d">$Conf{TarClientCmd}</A> for full details.</p>
3949     </dd>
3950     <dd>
3951     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = ``tar''.</p>
3952     </dd>
3953     <dd>
3954     <p>If you want to disable direct restores using tar, you should set
3955     <a href="#item_%24conf%7btarclientrestorecmd%7d">$Conf{TarClientRestoreCmd}</A> to undef and the corresponding CGI
3956     restore option will be removed.</p>
3957     </dd>
3958     <p></p>
3959     <dt><strong><a name="item_%24conf%7btarclientpath%7d">$Conf{TarClientPath} = '/bin/tar';</a></strong><br />
3960     </dt>
3961     <dd>
3962     Full path for tar on the client. Security caution: normal users should not
3963     allowed to write to this file or directory.
3964     </dd>
3965     <dd>
3966     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'tar'.</p>
3967     </dd>
3968     <p></p>
3969     <dt><strong><a name="item_%24conf%7brsyncclientpath%7d">$Conf{RsyncClientPath} = '/bin/rsync';</a></strong><br />
3970     </dt>
3971     <dd>
3972     Path to rsync executable on the client
3973     </dd>
3974     <p></p>
3975     <dt><strong><a name="item_%24conf%7brsyncclientcmd%7d">$Conf{RsyncClientCmd} = '$sshPath -q -x -l root $host $rsyncPath $argList+';</a></strong><br />
3976     </dt>
3977     <dd>
3978     Full command to run rsync on the client machine. The following variables
3979     are substituted at run-time:
3980     </dd>
3981     <dd>
3982     <pre>
3983     $host host name being backed up
3984     $hostIP host's IP address
3985     $shareName share name to backup (ie: top-level directory path)
3986     $rsyncPath same as <a href="#item_%24conf%7brsyncclientpath%7d">$Conf{RsyncClientPath}</A>
3987     $sshPath same as <a href="#item_%24conf%7bsshpath%7d">$Conf{SshPath}</A>
3988     $argList argument list, built from <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A>,
3989     $shareName, <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> and
3990     <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A></pre>
3991     </dd>
3992     <dd>
3993     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'rsync'.</p>
3994     </dd>
3995     <p></p>
3996     <dt><strong><a name="item_%24conf%7brsyncclientrestorecmd%7d">$Conf{RsyncClientRestoreCmd} = '$sshPath -q -x -l root $host $rsyncPath $argList+';</a></strong><br />
3997     </dt>
3998     <dd>
3999     Full command to run rsync for restore on the client. The following
4000     variables are substituted at run-time:
4001     </dd>
4002     <dd>
4003     <pre>
4004     $host host name being backed up
4005     $hostIP host's IP address
4006     $shareName share name to backup (ie: top-level directory path)
4007     $rsyncPath same as <a href="#item_%24conf%7brsyncclientpath%7d">$Conf{RsyncClientPath}</A>
4008     $sshPath same as <a href="#item_%24conf%7bsshpath%7d">$Conf{SshPath}</A>
4009     $argList argument list, built from <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A>,
4010     $shareName, <a href="#item_%24conf%7bbackupfilesexclude%7d">$Conf{BackupFilesExclude}</A> and
4011     <a href="#item_%24conf%7bbackupfilesonly%7d">$Conf{BackupFilesOnly}</A></pre>
4012     </dd>
4013     <dd>
4014     <p>This setting only matters if <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = 'rsync'.</p>
4015     </dd>
4016     <p></p>
4017     <dt><strong><a name="item_%24conf%7brsyncsharename%7d">$Conf{RsyncShareName} = '/';</a></strong><br />
4018     </dt>
4019     <dd>
4020     Share name to backup. For <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = ``rsync'' this should
4021     be a file system path, eg '/' or '/home'.
4022     </dd>
4023     <dd>
4024     <p>For <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = ``rsyncd'' this should be the name of the module
4025     to backup (ie: the name from /etc/rsynd.conf).</p>
4026     </dd>
4027     <dd>
4028     <p>This can also be a list of multiple file system paths or modules.
4029     For example, by adding --one-file-system to <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A> you
4030     can backup each file system separately, which makes restoring one
4031     bad file system easier. In this case you would list all of the mount
4032     points:</p>
4033     </dd>
4034     <dd>
4035     <pre>
4036     <a href="#item_%24conf%7brsyncsharename%7d">$Conf{RsyncShareName}</A> = ['/', '/var', '/data', '/boot'];</pre>
4037     </dd>
4038     <p></p>
4039     <dt><strong><a name="item_%24conf%7brsyncdclientport%7d">$Conf{RsyncdClientPort} = 873;</a></strong><br />
4040     </dt>
4041     <dd>
4042     Rsync daemon port on the client, for <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = ``rsyncd''.
4043     </dd>
4044     <p></p>
4045     <dt><strong><a name="item_%24conf%7brsyncdusername%7d">$Conf{RsyncdUserName} = '';</a></strong><br />
4046     </dt>
4047     <dd>
4048     Rsync daemon user name on client, for <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = ``rsyncd''.
4049     The user name and password are stored on the client in whatever file
4050     the ``secrets file'' parameter in rsyncd.conf points to
4051     (eg: /etc/rsyncd.secrets).
4052     </dd>
4053     <p></p>
4054     <dt><strong><a name="item_%24conf%7brsyncdpasswd%7d">$Conf{RsyncdPasswd} = '';</a></strong><br />
4055     </dt>
4056     <dd>
4057     Rsync daemon user name on client, for <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> = ``rsyncd''.
4058     The user name and password are stored on the client in whatever file
4059     the ``secrets file'' parameter in rsyncd.conf points to
4060     (eg: /etc/rsyncd.secrets).
4061     </dd>
4062     <p></p>
4063     <dt><strong><a name="item_%24conf%7brsyncdauthrequired%7d">$Conf{RsyncdAuthRequired} = 1;</a></strong><br />
4064     </dt>
4065     <dd>
4066     Whether authentication is mandatory when connecting to the client's
4067     rsyncd. By default this is on, ensuring that BackupPC will refuse to
4068     connect to an rsyncd on the client that is not password protected.
4069     Turn off at your own risk.
4070     </dd>
4071     <p></p>
4072     <dt><strong><a name="item_%24conf%7brsynccsumcacheverifyprob%7d">$Conf{RsyncCsumCacheVerifyProb} = 0.01;</a></strong><br />
4073     </dt>
4074     <dd>
4075     When rsync checksum caching is enabled (by adding the
4076     --checksum-seed=32761 option to <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A>), the cached
4077     checksums can be occaisonally verified to make sure the file
4078     contents matches the cached checksums. This is to avoid the
4079     risk that disk problems might cause the pool file contents to
4080     get corrupted, but the cached checksums would make BackupPC
4081     think that the file still matches the client.
4082     </dd>
4083     <dd>
4084     <p>This setting is the probability (0 means never and 1 means always)
4085     that a file will be rechecked. Setting it to 0 means the checksums
4086     will not be rechecked (unless there is a phase 0 failure). Setting
4087     it to 1 (ie: 100%) means all files will be checked, but that is
4088     not a desirable setting since you are better off simply turning
4089     caching off (ie: remove the --checksum-seed option).</p>
4090     </dd>
4091     <dd>
4092     <p>The default of 0.01 means 1% (on average) of the files during a full
4093     backup will have their cached checksum re-checked.</p>
4094     </dd>
4095     <dd>
4096     <p>This setting has no effect unless checksum caching is turned on.</p>
4097     </dd>
4098     <p></p>
4099     <dt><strong><a name="item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs} = [ ... ];</a></strong><br />
4100     </dt>
4101     <dd>
4102     Arguments to rsync for backup. Do not edit the first set unless you
4103     have a thorough understanding of how File::RsyncP works.
4104     </dd>
4105     <dd>
4106     <p>Examples of additional arguments that should work are --exclude/--include,
4107     eg:</p>
4108     </dd>
4109     <dd>
4110     <pre>
4111     <a href="#item_%24conf%7brsyncargs%7d">$Conf{RsyncArgs}</A> = [
4112     # original arguments here
4113     '-v',
4114     '--exclude', '/proc',
4115     '--exclude', '*.tmp',
4116     ];</pre>
4117     </dd>
4118     <p></p>
4119     <dt><strong><a name="item_%24conf%7brsyncrestoreargs%7d">$Conf{RsyncRestoreArgs} = [ ... ];</a></strong><br />
4120     </dt>
4121     <dd>
4122     Arguments to rsync for restore. Do not edit the first set unless you
4123     have a thorough understanding of how File::RsyncP works.
4124     </dd>
4125     <dd>
4126     <p>If you want to disable direct restores using rsync (eg: is the module
4127     is read-only), you should set <a href="#item_%24conf%7brsyncrestoreargs%7d">$Conf{RsyncRestoreArgs}</A> to undef and
4128     the corresponding CGI restore option will be removed.</p>
4129     </dd>
4130     <p></p>
4131     <dt><strong><a name="item_%24conf%7barchivedest%7d">$Conf{ArchiveDest} = '/tmp';</a></strong><br />
4132     </dt>
4133     <dd>
4134     Archive Destination
4135     </dd>
4136     <dd>
4137     <p>The Destination of the archive
4138     e.g. /tmp for file archive or /dev/nst0 for device archive</p>
4139     </dd>
4140     <p></p>
4141     <dt><strong><a name="item_%24conf%7barchivecomp%7d">$Conf{ArchiveComp} = 'gzip';</a></strong><br />
4142     </dt>
4143     <dd>
4144     Archive Compression type
4145     </dd>
4146     <dd>
4147     <p>The valid values are:</p>
4148     </dd>
4149     <dd>
4150     <pre>
4151     - 'none': No Compression</pre>
4152     </dd>
4153     <dd>
4154     <pre>
4155     - 'gzip': Medium Compression. Recommended.</pre>
4156     </dd>
4157     <dd>
4158     <pre>
4159     - 'bzip2': High Compression but takes longer.</pre>
4160     </dd>
4161     <p></p>
4162     <dt><strong><a name="item_%24conf%7barchivepar%7d">$Conf{ArchivePar} = 0;</a></strong><br />
4163     </dt>
4164     <dd>
4165     Archive Parity Files
4166     </dd>
4167     <dd>
4168     <p>The amount of Parity data to generate, as a percentage
4169     of the archive size.
4170     Uses the commandline par2 (par2cmdline) available from
4171     <a href="http://parchive.sourceforge.net">http://parchive.sourceforge.net</a></p>
4172     </dd>
4173     <dd>
4174     <p>Only useful for file dumps.</p>
4175     </dd>
4176     <dd>
4177     <p>Set to 0 to disable this feature.</p>
4178     </dd>
4179     <p></p>
4180     <dt><strong><a name="item_%24conf%7barchivesplit%7d">$Conf{ArchiveSplit} = 0;</a></strong><br />
4181     </dt>
4182     <dd>
4183     Archive Size Split
4184     </dd>
4185     <dd>
4186     <p>Only for file archives. Splits the output into
4187     the specified size * 1,000,000.
4188     e.g. to split into 650,000,000 bytes, specify 650 below.</p>
4189     </dd>
4190     <dd>
4191     <p>If the value is 0, or if <a href="#item_%24conf%7barchivedest%7d">$Conf{ArchiveDest}</A> is an existing file or
4192     device (e.g. a streaming tape drive), this feature is disabled.</p>
4193     </dd>
4194     <p></p>
4195     <dt><strong><a name="item_%24conf%7barchiveclientcmd%7d">$Conf{ArchiveClientCmd} = '$Installdir/bin/BackupPC_archiveHost' ...</a></strong><br />
4196     </dt>
4197     <dd>
4198     Archive Command
4199     </dd>
4200     <dd>
4201     <p>This is the command that is called to actually run the archive process
4202     for each host. The following variables are substituted at run-time:</p>
4203     </dd>
4204     <dd>
4205     <pre>
4206     $Installdir The installation directory of BackupPC
4207     $tarCreatePath The path to BackupPC_tarCreate
4208     $splitpath The path to the split program
4209     $parpath The path to the par2 program
4210     $host The host to archive
4211     $backupnumber The backup number of the host to archive
4212     $compression The path to the compression program
4213     $compext The extension assigned to the compression type
4214     $splitsize The number of bytes to split archives into
4215     $archiveloc The location to put the archive
4216     $parfile The amount of parity data to create (percentage)</pre>
4217     </dd>
4218     <p></p>
4219     <dt><strong><a name="item_%24conf%7bsshpath%7d">$Conf{SshPath} = '/usr/bin/ssh';</a></strong><br />
4220     </dt>
4221     <dd>
4222     Full path for ssh. Security caution: normal users should not
4223     allowed to write to this file or directory.
4224     </dd>
4225     <p></p>
4226     <dt><strong><a name="item_%24conf%7bnmblookuppath%7d">$Conf{NmbLookupPath} = '/usr/bin/nmblookup';</a></strong><br />
4227     </dt>
4228     <dd>
4229     Full path for nmblookup. Security caution: normal users should not
4230     allowed to write to this file or directory.
4231     </dd>
4232     <dd>
4233     <p>nmblookup is from the Samba distribution. nmblookup is used to get the
4234     netbios name, necessary for DHCP hosts.</p>
4235     </dd>
4236     <p></p>
4237     <dt><strong><a name="item_%24conf%7bnmblookupcmd%7d">$Conf{NmbLookupCmd} = '$nmbLookupPath -A $host';</a></strong><br />
4238     </dt>
4239     <dd>
4240     NmbLookup command. Given an IP address, does an nmblookup on that
4241     IP address. The following variables are substituted at run-time:
4242     </dd>
4243     <dd>
4244     <pre>
4245     $nmbLookupPath path to nmblookup (<a href="#item_%24conf%7bnmblookuppath%7d">$Conf{NmbLookupPath}</A>)
4246     $host IP address</pre>
4247     </dd>
4248     <dd>
4249     <p>This command is only used for DHCP hosts: given an IP address, this
4250     command should try to find its NetBios name.</p>
4251     </dd>
4252     <p></p>
4253     <dt><strong><a name="item_%24conf%7bnmblookupfindhostcmd%7d">$Conf{NmbLookupFindHostCmd} = '$nmbLookupPath $host';</a></strong><br />
4254     </dt>
4255     <dd>
4256     NmbLookup command. Given a netbios name, finds that host by doing
4257     a NetBios lookup. Several variables are substituted at run-time:
4258     </dd>
4259     <dd>
4260     <pre>
4261     $nmbLookupPath path to nmblookup (<a href="#item_%24conf%7bnmblookuppath%7d">$Conf{NmbLookupPath}</A>)
4262     $host NetBios name</pre>
4263     </dd>
4264     <dd>
4265     <p>In some cases you might need to change the broadcast address, for
4266     example if nmblookup uses 192.168.255.255 by default and you find
4267     that doesn't work, try 192.168.1.255 (or your equivalent class C
4268     address) using the -B option:</p>
4269     </dd>
4270     <dd>
4271     <pre>
4272     <a href="#item_%24conf%7bnmblookupfindhostcmd%7d">$Conf{NmbLookupFindHostCmd}</A> = '$nmbLookupPath -B 192.168.1.255 $host';</pre>
4273     </dd>
4274     <dd>
4275     <p>If you use a WINS server and your machines don't respond to
4276     multicast NetBios requests you can use this (replace 1.2.3.4
4277     with the IP address of your WINS server):</p>
4278     </dd>
4279     <dd>
4280     <pre>
4281     <a href="#item_%24conf%7bnmblookupfindhostcmd%7d">$Conf{NmbLookupFindHostCmd}</A> = '$nmbLookupPath -R -U 1.2.3.4 $host';</pre>
4282     </dd>
4283     <dd>
4284     <p>This is preferred over multicast since it minimizes network traffic.</p>
4285     </dd>
4286     <dd>
4287     <p>Experiment manually for your site to see what form of nmblookup command
4288     works.</p>
4289     </dd>
4290     <p></p>
4291     <dt><strong><a name="item_%24conf%7bfixedipnetbiosnamecheck%7d">$Conf{FixedIPNetBiosNameCheck} = 0;</a></strong><br />
4292     </dt>
4293     <dd>
4294     For fixed IP address hosts, BackupPC_dump can also verify the netbios
4295     name to ensure it matches the host name. An error is generated if
4296     they do not match. Typically this flag is off. But if you are going
4297     to transition a bunch of machines from fixed host addresses to DHCP,
4298     setting this flag is a great way to verify that the machines have
4299     their netbios name set correctly before turning on DCHP.
4300     </dd>
4301     <p></p>
4302     <dt><strong><a name="item_%24conf%7bpingpath%7d">$Conf{PingPath} = '/bin/ping';</a></strong><br />
4303     </dt>
4304     <dd>
4305     Full path to the ping command. Security caution: normal users
4306     should not be allowed to write to this file or directory.
4307     </dd>
4308     <dd>
4309     <p>If you want to disable ping checking, set this to some program
4310     that exits with 0 status, eg:</p>
4311     </dd>
4312     <dd>
4313     <pre>
4314     <a href="#item_%24conf%7bpingpath%7d">$Conf{PingPath}</A> = '/bin/echo';</pre>
4315     </dd>
4316     <p></p>
4317     <dt><strong><a name="item_%24conf%7bpingcmd%7d">$Conf{PingCmd} = '$pingPath -c 1 $host';</a></strong><br />
4318     </dt>
4319     <dd>
4320     Ping command. The following variables are substituted at run-time:
4321     </dd>
4322     <dd>
4323     <pre>
4324     $pingPath path to ping (<a href="#item_%24conf%7bpingpath%7d">$Conf{PingPath}</A>)
4325     $host host name</pre>
4326     </dd>
4327     <dd>
4328     <p>Wade Brown reports that on solaris 2.6 and 2.7 ping -s returns the wrong
4329     exit status (0 even on failure). Replace with ``ping $host 1'', which
4330     gets the correct exit status but we don't get the round-trip time.</p>
4331     </dd>
4332     <p></p>
4333     <dt><strong><a name="item_%24conf%7bserverinitdpath%7d">$Conf{ServerInitdPath} = '';</a></strong><br />
4334     </dt>
4335     <dt><strong><a name="item_%24conf%7bserverinitdstartcmd%7d">$Conf{ServerInitdStartCmd} = '';</a></strong><br />
4336     </dt>
4337     <dd>
4338     Path to init.d script and command to use that script to start the
4339     server from the CGI interface. The following variables are substituted
4340     at run-time:
4341     </dd>
4342     <dd>
4343     <pre>
4344     $sshPath path to ssh (<a href="#item_%24conf%7bsshpath%7d">$Conf{SshPath}</A>)
4345     $serverHost same as <a href="#item_%24conf%7bserverhost%7d">$Conf{ServerHost}</A>
4346     $serverInitdPath path to init.d script (<a href="#item_%24conf%7bserverinitdpath%7d">$Conf{ServerInitdPath}</A>)</pre>
4347     </dd>
4348     <dd>
4349     <p>Example:</p>
4350     </dd>
4351     <dd>
4352     <p><a href="#item_%24conf%7bserverinitdpath%7d">$Conf{ServerInitdPath}</A> = '/etc/init.d/backuppc';
4353     <a href="#item_%24conf%7bserverinitdstartcmd%7d">$Conf{ServerInitdStartCmd}</A> = '$sshPath -q -x -l root $serverHost'
4354     . ' $serverInitdPath start'
4355     . ' &lt; /dev/null &gt;&amp; /dev/null';</p>
4356     </dd>
4357     <p></p>
4358     <dt><strong><a name="item_%24conf%7bcompresslevel%7d">$Conf{CompressLevel} = 0;</a></strong><br />
4359     </dt>
4360     <dd>
4361     Compression level to use on files. 0 means no compression. Compression
4362     levels can be from 1 (least cpu time, slightly worse compression) to
4363     9 (most cpu time, slightly better compression). The recommended value
4364     is 3. Changing to 5, for example, will take maybe 20% more cpu time
4365     and will get another 2-3% additional compression. See the zlib
4366     documentation for more information about compression levels.
4367     </dd>
4368     <dd>
4369     <p>Changing compression on or off after backups have already been done
4370     will require both compressed and uncompressed pool files to be stored.
4371     This will increase the pool storage requirements, at least until all
4372     the old backups expire and are deleted.</p>
4373     </dd>
4374     <dd>
4375     <p>It is ok to change the compression value (from one non-zero value to
4376     another non-zero value) after dumps are already done. Since BackupPC
4377     matches pool files by comparing the uncompressed versions, it will still
4378     correctly match new incoming files against existing pool files. The
4379     new compression level will take effect only for new files that are
4380     newly compressed and added to the pool.</p>
4381     </dd>
4382     <dd>
4383     <p>If compression was off and you are enabling compression for the first
4384     time you can use the BackupPC_compressPool utility to compress the
4385     pool. This avoids having the pool grow to accommodate both compressed
4386     and uncompressed backups. See the documentation for more information.</p>
4387     </dd>
4388     <dd>
4389     <p>Note: compression needs the Compress::Zlib perl library. If the
4390     Compress::Zlib library can't be found then <a href="#item_%24conf%7bcompresslevel%7d">$Conf{CompressLevel}</A> is
4391     forced to 0 (compression off).</p>
4392     </dd>
4393     <p></p>
4394     <dt><strong><a name="item_%24conf%7bpingmaxmsec%7d">$Conf{PingMaxMsec} = 20;</a></strong><br />
4395     </dt>
4396     <dd>
4397     Maximum round-trip ping time in milliseconds. This threshold is set
4398     to avoid backing up PCs that are remotely connected through WAN or
4399     dialup connections. The output from ping -s (assuming it is supported
4400     on your system) is used to check the round-trip packet time. On your
4401     local LAN round-trip times should be much less than 20msec. On most
4402     WAN or dialup connections the round-trip time will be typically more
4403     than 20msec. Tune if necessary.
4404     </dd>
4405     <p></p>
4406     <dt><strong><a name="item_%24conf%7bclienttimeout%7d">$Conf{ClientTimeout} = 7200;</a></strong><br />
4407     </dt>
4408     <dd>
4409     Timeout in seconds when listening for the transport program's
4410     (smbclient, tar etc) stdout. If no output is received during this
4411     time, then it is assumed that something has wedged during a backup,
4412     and the backup is terminated.
4413     </dd>
4414     <dd>
4415     <p>Note that stdout buffering combined with huge files being backed up
4416     could cause longish delays in the output from smbclient that
4417     BackupPC_dump sees, so in rare cases you might want to increase
4418     this value.</p>
4419     </dd>
4420     <dd>
4421     <p>Despite the name, this parameter sets the timeout for all transport
4422     methods (tar, smb etc).</p>
4423     </dd>
4424     <p></p>
4425     <dt><strong><a name="item_%24conf%7bmaxoldperpclogfiles%7d">$Conf{MaxOldPerPCLogFiles} = 12;</a></strong><br />
4426     </dt>
4427     <dd>
4428     Maximum number of log files we keep around in each PC's directory
4429     (ie: pc/$host). These files are aged monthly. A setting of 12
4430     means there will be at most the files LOG, LOG.0, LOG.1, ... LOG.11
4431     in the pc/$host directory (ie: about a years worth). (Except this
4432     month's LOG, these files will have a .z extension if compression
4433     is on).
4434     </dd>
4435     <dd>
4436     <p>If you decrease this number after BackupPC has been running for a
4437     while you will have to manually remove the older log files.</p>
4438     </dd>
4439     <p></p>
4440     <dt><strong><a name="item_%24conf%7bdumppreusercmd%7d">$Conf{DumpPreUserCmd} = undef;</a></strong><br />
4441     </dt>
4442     <dt><strong><a name="item_%24conf%7bdumppostusercmd%7d">$Conf{DumpPostUserCmd} = undef;</a></strong><br />
4443     </dt>
4444     <dt><strong><a name="item_%24conf%7brestorepreusercmd%7d">$Conf{RestorePreUserCmd} = undef;</a></strong><br />
4445     </dt>
4446     <dt><strong><a name="item_%24conf%7brestorepostusercmd%7d">$Conf{RestorePostUserCmd} = undef;</a></strong><br />
4447     </dt>
4448     <dt><strong><a name="item_%24conf%7barchivepreusercmd%7d">$Conf{ArchivePreUserCmd} = undef;</a></strong><br />
4449     </dt>
4450     <dt><strong><a name="item_%24conf%7barchivepostusercmd%7d">$Conf{ArchivePostUserCmd} = undef;</a></strong><br />
4451     </dt>
4452     <dd>
4453     Optional commands to run before and after dumps and restores.
4454     Stdout from these commands will be written to the Xfer (or Restore)
4455     log file. One example of using these commands would be to
4456     shut down and restart a database server, or to dump a database
4457     to files for backup. Example:
4458     </dd>
4459     <dd>
4460     <pre>
4461     <a href="#item_%24conf%7bdumppreusercmd%7d">$Conf{DumpPreUserCmd}</A> = '$sshPath -q -x -l root $host /usr/bin/dumpMysql';</pre>
4462     </dd>
4463     <dd>
4464     <p>The following variable substitutions are made at run time for
4465     <a href="#item_%24conf%7bdumppreusercmd%7d">$Conf{DumpPreUserCmd}</A> and <a href="#item_%24conf%7bdumppostusercmd%7d">$Conf{DumpPostUserCmd}</A>:</p>
4466     </dd>
4467     <dd>
4468     <pre>
4469     $type type of dump (incr or full)
4470     $xferOK 1 if the dump succeeded, 0 if it didn't
4471     $client client name being backed up
4472     $host host name (could be different from client name if
4473     <a href="#item_%24conf%7bclientnamealias%7d">$Conf{ClientNameAlias}</A> is set)
4474     $hostIP IP address of host
4475     $user user name from the hosts file
4476     $moreUsers list of additional users from the hosts file
4477     $share the first share name
4478     $shares list of all the share names
4479     $XferMethod value of <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> (eg: tar, rsync, smb)
4480     $sshPath value of <a href="#item_%24conf%7bsshpath%7d">$Conf{SshPath}</A>,
4481     $cmdType set to DumpPreUserCmd or DumpPostUserCmd</pre>
4482     </dd>
4483     <dd>
4484     <p>The following variable substitutions are made at run time for
4485     <a href="#item_%24conf%7brestorepreusercmd%7d">$Conf{RestorePreUserCmd}</A> and <a href="#item_%24conf%7brestorepostusercmd%7d">$Conf{RestorePostUserCmd}</A>:</p>
4486     </dd>
4487     <dd>
4488     <pre>
4489     $client client name being backed up
4490     $xferOK 1 if the restore succeeded, 0 if it didn't
4491     $host host name (could be different from client name if
4492     <a href="#item_%24conf%7bclientnamealias%7d">$Conf{ClientNameAlias}</A> is set)
4493     $hostIP IP address of host
4494     $user user name from the hosts file
4495     $moreUsers list of additional users from the hosts file
4496     $share the first share name
4497     $XferMethod value of <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> (eg: tar, rsync, smb)
4498     $sshPath value of <a href="#item_%24conf%7bsshpath%7d">$Conf{SshPath}</A>,
4499     $type set to &quot;restore&quot;
4500     $bkupSrcHost host name of the restore source
4501     $bkupSrcShare share name of the restore source
4502     $bkupSrcNum backup number of the restore source
4503     $pathHdrSrc common starting path of restore source
4504     $pathHdrDest common starting path of destination
4505     $fileList list of files being restored
4506     $cmdType set to RestorePreUserCmd or RestorePostUserCmd</pre>
4507     </dd>
4508     <dd>
4509     <p>The following variable substitutions are made at run time for
4510     <a href="#item_%24conf%7barchivepreusercmd%7d">$Conf{ArchivePreUserCmd}</A> and <a href="#item_%24conf%7barchivepostusercmd%7d">$Conf{ArchivePostUserCmd}</A>:</p>
4511     </dd>
4512     <dd>
4513     <pre>
4514     $client client name being backed up
4515     $xferOK 1 if the archive succeeded, 0 if it didn't
4516     $host Name of the archive host
4517     $user user name from the hosts file
4518     $share the first share name
4519     $XferMethod value of <a href="#item_%24conf%7bxfermethod%7d">$Conf{XferMethod}</A> (eg: tar, rsync, smb)
4520     $HostList list of hosts being archived
4521     $BackupList list of backup numbers for the hosts being archived
4522     $archiveloc location where the archive is sent to
4523     $parfile amount of parity data being generated (percentage)
4524     $compression compression program being used (eg: cat, gzip, bzip2)
4525     $compext extension used for compression type (eg: raw, gz, bz2)
4526     $splitsize size of the files that the archive creates
4527     $sshPath value of <a href="#item_%24conf%7bsshpath%7d">$Conf{SshPath}</A>,
4528     $type set to &quot;archive&quot;
4529     $cmdType set to ArchivePreUserCmd or ArchivePostUserCmd</pre>
4530     </dd>
4531     <p></p>
4532     <dt><strong><a name="item_%24conf%7bclientnamealias%7d">$Conf{ClientNameAlias} = undef;</a></strong><br />
4533     </dt>
4534     <dd>
4535     Override the client's host name. This allows multiple clients
4536     to all refer to the same physical host. This should only be
4537     set in the per-PC config file and is only used by BackupPC at
4538     the last moment prior to generating the command used to backup
4539     that machine (ie: the value of <a href="#item_%24conf%7bclientnamealias%7d">$Conf{ClientNameAlias}</A> is invisible
4540     everywhere else in BackupPC). The setting can be a host name or
4541     IP address, eg:
4542     </dd>
4543     <dd>
4544     <pre>
4545     <a href="#item_%24conf%7bclientnamealias%7d">$Conf{ClientNameAlias}</A> = 'realHostName';
4546     <a href="#item_%24conf%7bclientnamealias%7d">$Conf{ClientNameAlias}</A> = '192.1.1.15';</pre>
4547     </dd>
4548     <dd>
4549     <p>will cause the relevant smb/tar/rsync backup/restore commands to be
4550     directed to realHostName, not the client name.</p>
4551     </dd>
4552     <dd>
4553     <p>Note: this setting doesn't work for hosts with DHCP set to 1.</p>
4554     </dd>
4555     <p></p>
4556     <dt><strong><a name="item_%24conf%7bperlmoduleload%7d">$Conf{PerlModuleLoad} = undef;</a></strong><br />
4557     </dt>
4558     <dd>
4559     Advanced option for asking BackupPC to load additional perl modules.
4560     Can be a list (array ref) of module names to load at startup.
4561     </dd>
4562     <p></p></dl>
4563     <p>
4564     </p>
4565     <h2><a name="email_reminders__status_and_messages">Email reminders, status and messages</a></h2>
4566     <dl>
4567     <dt><strong><a name="item_%24conf%7bsendmailpath%7d">$Conf{SendmailPath} = '/usr/sbin/sendmail';</a></strong><br />
4568     </dt>
4569     <dd>
4570     Full path to the sendmail command. Security caution: normal users
4571     should not allowed to write to this file or directory.
4572     </dd>
4573     <p></p>
4574     <dt><strong><a name="item_%24conf%7bemailnotifymindays%7d">$Conf{EMailNotifyMinDays} = 2.5;</a></strong><br />
4575     </dt>
4576     <dd>
4577     Minimum period between consecutive emails to a single user.
4578     This tries to keep annoying email to users to a reasonable
4579     level. Email checks are done nightly, so this number is effectively
4580     rounded up (ie: 2.5 means a user will never receive email more
4581     than once every 3 days).
4582     </dd>
4583     <p></p>
4584     <dt><strong><a name="item_%24conf%7bemailfromusername%7d">$Conf{EMailFromUserName} = '';</a></strong><br />
4585     </dt>
4586     <dd>
4587     Name to use as the ``from'' name for email. Depending upon your mail
4588     handler this is either a plain name (eg: ``admin'') or a fully-qualified
4589     name (eg: <a href="mailto:``admin@mydomain.com'').">``admin@mydomain.com'').</a>
4590     </dd>
4591     <p></p>
4592     <dt><strong><a name="item_%24conf%7bemailadminusername%7d">$Conf{EMailAdminUserName} = '';</a></strong><br />
4593     </dt>
4594     <dd>
4595     Destination address to an administrative user who will receive a
4596     nightly email with warnings and errors. If there are no warnings
4597     or errors then no email will be sent. Depending upon your mail
4598     handler this is either a plain name (eg: ``admin'') or a fully-qualified
4599     name (eg: <a href="mailto:``admin@mydomain.com'').">``admin@mydomain.com'').</a>
4600     </dd>
4601     <p></p>
4602     <dt><strong><a name="item_%24conf%7bemailuserdestdomain%7d">$Conf{EMailUserDestDomain} = '';</a></strong><br />
4603     </dt>
4604     <dd>
4605     Destination domain name for email sent to users. By default
4606     this is empty, meaning email is sent to plain, unqualified
4607     addresses. Otherwise, set it to the destintation domain, eg:
4608     </dd>
4609     <dd>
4610     <pre>
4611     $Cong{EMailUserDestDomain} = '@mydomain.com';</pre>
4612     </dd>
4613     <dd>
4614     <p>With this setting user email will be set to <a href="mailto:'user@mydomain.com'.">'user@mydomain.com'.</a></p>
4615     </dd>
4616     <p></p>
4617     <dt><strong><a name="item_%24conf%7bemailnobackupeversubj%7d">$Conf{EMailNoBackupEverSubj} = undef;</a></strong><br />
4618     </dt>
4619     <dt><strong><a name="item_%24conf%7bemailnobackupevermesg%7d">$Conf{EMailNoBackupEverMesg} = undef;</a></strong><br />
4620     </dt>
4621     <dd>
4622     This subject and message is sent to a user if their PC has never been
4623     backed up.
4624     </dd>
4625     <dd>
4626     <p>These values are language-dependent. The default versions can be
4627     found in the language file (eg: lib/BackupPC/Lang/en.pm). If you
4628     need to change the message, copy it here and edit it, eg:</p>
4629     </dd>
4630     <dd>
4631     <pre>
4632     <a href="#item_%24conf%7bemailnobackupevermesg%7d">$Conf{EMailNoBackupEverMesg}</A> = &lt;&lt;'EOF';
4633     To: $user$domain
4634     cc:
4635     Subject: $subj</pre>
4636     </dd>
4637     <dd>
4638     <pre>
4639     Dear $userName,</pre>
4640     </dd>
4641     <dd>
4642     <pre>
4643     This is a site-specific email message.
4644     EOF</pre>
4645     </dd>
4646     <p></p>
4647     <dt><strong><a name="item_%24conf%7bemailnotifyoldbackupdays%7d">$Conf{EMailNotifyOldBackupDays} = 7.0;</a></strong><br />
4648     </dt>
4649     <dd>
4650     How old the most recent backup has to be before notifying user.
4651     When there have been no backups in this number of days the user
4652     is sent an email.
4653     </dd>
4654     <p></p>
4655     <dt><strong><a name="item_%24conf%7bemailnobackuprecentsubj%7d">$Conf{EMailNoBackupRecentSubj} = undef;</a></strong><br />
4656     </dt>
4657     <dt><strong><a name="item_%24conf%7bemailnobackuprecentmesg%7d">$Conf{EMailNoBackupRecentMesg} = undef;</a></strong><br />
4658     </dt>
4659     <dd>
4660     This subject and message is sent to a user if their PC has not recently
4661     been backed up (ie: more than <a href="#item_%24conf%7bemailnotifyoldbackupdays%7d">$Conf{EMailNotifyOldBackupDays}</A> days ago).
4662     </dd>
4663     <dd>
4664     <p>These values are language-dependent. The default versions can be
4665     found in the language file (eg: lib/BackupPC/Lang/en.pm). If you
4666     need to change the message, copy it here and edit it, eg:</p>
4667     </dd>
4668     <dd>
4669     <pre>
4670     <a href="#item_%24conf%7bemailnobackuprecentmesg%7d">$Conf{EMailNoBackupRecentMesg}</A> = &lt;&lt;'EOF';
4671     To: $user$domain
4672     cc:
4673     Subject: $subj</pre>
4674     </dd>
4675     <dd>
4676     <pre>
4677     Dear $userName,</pre>
4678     </dd>
4679     <dd>
4680     <pre>
4681     This is a site-specific email message.
4682     EOF</pre>
4683     </dd>
4684     <p></p>
4685     <dt><strong><a name="item_%24conf%7bemailnotifyoldoutlookdays%7d">$Conf{EMailNotifyOldOutlookDays} = 5.0;</a></strong><br />
4686     </dt>
4687     <dd>
4688     How old the most recent backup of Outlook files has to be before
4689     notifying user.
4690     </dd>
4691     <p></p>
4692     <dt><strong><a name="item_%24conf%7bemailoutlookbackupsubj%7d">$Conf{EMailOutlookBackupSubj} = undef;</a></strong><br />
4693     </dt>
4694     <dt><strong><a name="item_%24conf%7bemailoutlookbackupmesg%7d">$Conf{EMailOutlookBackupMesg} = undef;</a></strong><br />
4695     </dt>
4696     <dd>
4697     This subject and message is sent to a user if their Outlook files have
4698     not recently been backed up (ie: more than <a href="#item_%24conf%7bemailnotifyoldoutlookdays%7d">$Conf{EMailNotifyOldOutlookDays}</A>
4699     days ago).
4700     </dd>
4701     <dd>
4702     <p>These values are language-dependent. The default versions can be
4703     found in the language file (eg: lib/BackupPC/Lang/en.pm). If you
4704     need to change the message, copy it here and edit it, eg:</p>
4705     </dd>
4706     <dd>
4707     <pre>
4708     <a href="#item_%24conf%7bemailoutlookbackupmesg%7d">$Conf{EMailOutlookBackupMesg}</A> = &lt;&lt;'EOF';
4709     To: $user$domain
4710     cc:
4711     Subject: $subj</pre>
4712     </dd>
4713     <dd>
4714     <pre>
4715     Dear $userName,</pre>
4716     </dd>
4717     <dd>
4718     <pre>
4719     This is a site-specific email message.
4720     EOF</pre>
4721     </dd>
4722     <p></p></dl>
4723     <p>
4724     </p>
4725     <h2><a name="cgi_user_interface_configuration_settings">CGI user interface configuration settings</a></h2>
4726     <dl>
4727     <dt><strong><a name="item_%24conf%7bcgiadminusergroup%7d">$Conf{CgiAdminUserGroup} = '';</a></strong><br />
4728     </dt>
4729     <dt><strong><a name="item_%24conf%7bcgiadminusers%7d">$Conf{CgiAdminUsers} = '';</a></strong><br />
4730     </dt>
4731     <dd>
4732     Normal users can only access information specific to their host.
4733     They can start/stop/browse/restore backups.
4734     </dd>
4735     <dd>
4736     <p>Administrative users have full access to all hosts, plus overall
4737     status and log information.</p>
4738     </dd>
4739     <dd>
4740     <p>The administrative users are the union of the unix/linux group
4741     <a href="#item_%24conf%7bcgiadminusergroup%7d">$Conf{CgiAdminUserGroup}</A> and the manual list of users, separated
4742     by spaces, in <a href="#item_%24conf%7bcgiadminusers%7d">$Conf{CgiAdminUsers}</A>. If you don't want a group or
4743     manual list of users set the corresponding configuration setting
4744     to undef or an empty string.</p>
4745     </dd>
4746     <dd>
4747     <p>If you want every user to have admin privileges (careful!), set
4748     <a href="#item_%24conf%7bcgiadminusers%7d">$Conf{CgiAdminUsers}</A> = '*'.</p>
4749     </dd>
4750     <dd>
4751     <p>Examples:</p>
4752     </dd>
4753     <dd>
4754     <pre>
4755     <a href="#item_%24conf%7bcgiadminusergroup%7d">$Conf{CgiAdminUserGroup}</A> = 'admin';
4756     <a href="#item_%24conf%7bcgiadminusers%7d">$Conf{CgiAdminUsers}</A> = 'craig celia';
4757     --&gt; administrative users are the union of group admin, plus
4758     craig and celia.</pre>
4759     </dd>
4760     <dd>
4761     <pre>
4762     <a href="#item_%24conf%7bcgiadminusergroup%7d">$Conf{CgiAdminUserGroup}</A> = '';
4763     <a href="#item_%24conf%7bcgiadminusers%7d">$Conf{CgiAdminUsers}</A> = 'craig celia';
4764     --&gt; administrative users are only craig and celia'.</pre>
4765     </dd>
4766     <p></p>
4767     <dt><strong><a name="item_%24conf%7bcgiurl%7d">$Conf{CgiURL} = undef;</a></strong><br />
4768     </dt>
4769     <dd>
4770     URL of the BackupPC_Admin CGI script. Used for email messages.
4771     </dd>
4772     <p></p>
4773     <dt><strong><a name="item_%24conf%7blanguage%7d">$Conf{Language} = 'en';</a></strong><br />
4774     </dt>
4775     <dd>
4776     Language to use. See lib/BackupPC/Lang for the list of supported
4777     languages, which include English (en), French (fr), Spanish (es),
4778     German (de), Italian (it) and Dutch (nl).
4779     </dd>
4780     <dd>
4781     <p>Currently the Language setting applies to the CGI interface and email
4782     messages sent to users. Log files and other text are still in English.</p>
4783     </dd>
4784     <p></p>
4785     <dt><strong><a name="item_%24conf%7bcgiuserhomepagecheck%7d">$Conf{CgiUserHomePageCheck} = '';</a></strong><br />
4786     </dt>
4787     <dt><strong><a name="item_%24conf%7bcgiuserurlcreate%7d">$Conf{CgiUserUrlCreate} = 'mailto:%s';</a></strong><br />
4788     </dt>
4789     <dd>
4790     User names that are rendered by the CGI interface can be turned
4791     into links into their home page or other information about the
4792     user. To set this up you need to create two <code>sprintf()</code> strings,
4793     that each contain a single '%s' that will be replaced by the user
4794     name. The default is a mailto: link.
4795     </dd>
4796     <dd>
4797     <p><a href="#item_%24conf%7bcgiuserhomepagecheck%7d">$Conf{CgiUserHomePageCheck}</A> should be an absolute file path that
4798     is used to check (via ``-f'') that the user has a valid home page.
4799     Set this to undef or an empty string to turn off this check.</p>
4800     </dd>
4801     <dd>
4802     <p><a href="#item_%24conf%7bcgiuserurlcreate%7d">$Conf{CgiUserUrlCreate}</A> should be a full URL that points to the
4803     user's home page. Set this to undef or an empty string to turn
4804     off generation of URLs for user names.</p>
4805     </dd>
4806     <dd>
4807     <p>Example:</p>
4808     </dd>
4809     <dd>
4810     <pre>
4811     <a href="#item_%24conf%7bcgiuserhomepagecheck%7d">$Conf{CgiUserHomePageCheck}</A> = '/var/www/html/users/%s.html';
4812     <a href="#item_%24conf%7bcgiuserurlcreate%7d">$Conf{CgiUserUrlCreate}</A> = '<a href="http://myhost/users/%s.html">http://myhost/users/%s.html</a>';
4813     --&gt; if /var/www/html/users/craig.html exists, then 'craig' will
4814     be rendered as a link to <a href="http://myhost/users/craig.html">http://myhost/users/craig.html</a>.</pre>
4815     </dd>
4816     <p></p>
4817     <dt><strong><a name="item_%24conf%7bcgidateformatmmdd%7d">$Conf{CgiDateFormatMMDD} = 1;</a></strong><br />
4818     </dt>
4819     <dd>
4820     Date display format for CGI interface. True for US-style dates (MM/DD)
4821     and zero for international dates (DD/MM).
4822     </dd>
4823     <p></p>
4824     <dt><strong><a name="item_%24conf%7bcginavbaradminallhosts%7d">$Conf{CgiNavBarAdminAllHosts} = 1;</a></strong><br />
4825     </dt>
4826     <dd>
4827     If set, the complete list of hosts appears in the left navigation
4828     bar pull-down for administrators. Otherwise, just the hosts for which
4829     the user is listed in the host file (as either the user or in moreUsers)
4830     are displayed.
4831     </dd>
4832     <p></p>
4833     <dt><strong><a name="item_%24conf%7bcgisearchboxenable%7d">$Conf{CgiSearchBoxEnable} = 1;</a></strong><br />
4834     </dt>
4835     <dd>
4836     Enable/disable the search box in the navigation bar.
4837     </dd>
4838     <p></p>
4839     <dt><strong><a name="item_%24conf%7bcginavbarlinks%7d">$Conf{CgiNavBarLinks} = [ ... ];</a></strong><br />
4840     </dt>
4841     <dd>
4842     Additional navigation bar links. These appear for both regular users
4843     and administrators. This is a list of hashes giving the link (URL)
4844     and the text (name) for the link. Specifying lname instead of name
4845     uses the language specific string (ie: $Lang-&gt;{lname}) instead of
4846     just literally displaying name.
4847     </dd>
4848     <p></p>
4849     <dt><strong><a name="item_%24conf%7bcgistatushilightcolor%7d">$Conf{CgiStatusHilightColor} = { ...</a></strong><br />
4850     </dt>
4851     <dd>
4852     Hilight colors based on status that are used in the PC summary page.
4853     </dd>
4854     <p></p>
4855     <dt><strong><a name="item_%24conf%7bcgiheaders%7d">$Conf{CgiHeaders} = '&lt;meta http-equiv=``pragma'' content=``no-cache''&gt;';</a></strong><br />
4856     </dt>
4857     <dd>
4858     Additional CGI header text.
4859     </dd>
4860     <p></p>
4861     <dt><strong><a name="item_%24conf%7bcgiimagedir%7d">$Conf{CgiImageDir} = '';</a></strong><br />
4862     </dt>
4863     <dd>
4864     Directory where images are stored. This directory should be below
4865     Apache's DocumentRoot. This value isn't used by BackupPC but is
4866     used by configure.pl when you upgrade BackupPC.
4867     </dd>
4868     <dd>
4869     <p>Example:</p>
4870     </dd>
4871     <dd>
4872     <pre>
4873     <a href="#item_%24conf%7bcgiimagedir%7d">$Conf{CgiImageDir}</A> = '/usr/local/apache/htdocs/BackupPC';</pre>
4874     </dd>
4875     <p></p>
4876     <dt><strong><a name="item_%24conf%7bcgiext2contenttype%7d">$Conf{CgiExt2ContentType} = { };</a></strong><br />
4877     </dt>
4878     <dd>
4879     Additional mappings of file name extenions to Content-Type for
4880     individual file restore. See $Ext2ContentType in BackupPC_Admin
4881     for the default setting. You can add additional settings here,
4882     or override any default settings. Example:
4883     </dd>
4884     <dd>
4885     <pre>
4886     <a href="#item_%24conf%7bcgiext2contenttype%7d">$Conf{CgiExt2ContentType}</A> = {
4887     'pl' =&gt; 'text/plain',
4888     };</pre>
4889     </dd>
4890     <p></p>
4891     <dt><strong><a name="item_%24conf%7bcgiimagedirurl%7d">$Conf{CgiImageDirURL} = '';</a></strong><br />
4892     </dt>
4893     <dd>
4894     URL (without the leading <a href="http://host)">http://host)</a> for BackupPC's image directory.
4895     The CGI script uses this value to serve up image files.
4896     </dd>
4897     <dd>
4898     <p>Example:</p>
4899     </dd>
4900     <dd>
4901     <pre>
4902     <a href="#item_%24conf%7bcgiimagedirurl%7d">$Conf{CgiImageDirURL}</A> = '/BackupPC';</pre>
4903     </dd>
4904     <p></p>
4905     <dt><strong><a name="item_%24conf%7bcgicssfile%7d">$Conf{CgiCSSFile} = 'BackupPC_stnd.css';</a></strong><br />
4906     </dt>
4907     <dd>
4908     CSS stylesheet for the CGI interface. It is stored in the
4909     <a href="#item_%24conf%7bcgiimagedir%7d">$Conf{CgiImageDir}</A> directory and accessed via the
4910     <a href="#item_%24conf%7bcgiimagedirurl%7d">$Conf{CgiImageDirURL}</A> URL.
4911     </dd>
4912     <p></p></dl>
4913     <p>
4914     <a href="#__index__"><small>Back to Top</small></a>
4915     </p>
4916     <hr />
4917     <h1><a name="version_numbers">Version Numbers</a></h1>
4918     <p>Starting with v1.4.0 BackupPC uses a X.Y.Z version numbering system,
4919     instead of X.0Y. The first digit is for major new releases, the middle
4920     digit is for significant feature releases and improvements (most of
4921     the releases have been in this category), and the last digit is for
4922     bug fixes. You should think of the old 1.00, 1.01, 1.02 and 1.03 as
4923     1..0, 1.1.0, 1.2.0 and 1.3.0.</p>
4924     <p>Additionally, patches might be made available. A patched version
4925     number is of the form X.Y.ZplN (eg: 2.1.0pl2), where N is the
4926     patch level.</p>
4927     <p>
4928     <a href="#__index__"><small>Back to Top</small></a>
4929     </p>
4930     <hr />
4931     <h1><a name="author">Author</a></h1>
4932     <p>Craig Barratt &lt;<a href="mailto:cbarratt@users.sourceforge.net">cbarratt@users.sourceforge.net</a>&gt;</p>
4933     <p>See <a href="http://backuppc.sourceforge.net">http://backuppc.sourceforge.net</a>.</p>
4934     <p>
4935     <a href="#__index__"><small>Back to Top</small></a>
4936     </p>
4937     <hr />
4938     <h1><a name="copyright">Copyright</a></h1>
4939     <p>Copyright (C) 2001-2004 Craig Barratt</p>
4940     <p>
4941     <a href="#__index__"><small>Back to Top</small></a>
4942     </p>
4943     <hr />
4944     <h1><a name="credits">Credits</a></h1>
4945     <p>Ryan Kucera contributed the directory navigation code and images
4946     for v1.5.0. He contributed the first skeleton of BackupPC_restore.
4947     He also added a significant revision to the CGI interface, including
4948     CSS tags, in v2.1.0, and designed the BackupPC logo.</p>
4949     <p>Xavier Nicollet, with additions from Guillaume Filion, added the
4950     internationalization (i18n) support to the CGI interface for v2.0.0.
4951     Xavier provided the French translation fr.pm, with additions from
4952     Guillaume.</p>
4953     <p>Guillaume Filion wrote BackupPC_zipCreate and added the CGI support
4954     for zip download, in addition to some CGI cleanup, for v1.5.0.
4955     Guillaume continues to support fr.pm updates for each new version.</p>
4956     <p>Josh Marshall implemented the Archive feature in v2.1.0.</p>
4957     <p>Ludovic Drolez supports the BackupPC Debian package.</p>
4958     <p>Javier Gonzalez provided the Spanish translation, es.pm for v2.0.0.</p>
4959     <p>Manfred Herrmann provided the German translation, de.pm for v2.0.0.
4960     Manfred continues to support de.pm updates for each new version,
4961     together with some help frmo Ralph Paßgang.</p>
4962     <p>Lorenzo Cappelletti provided the Italian translation, it.pm for v2.1.0.</p>
4963     <p>Lieven Bridts provided the Dutch translation, nl.pm, for v2.1.0,
4964     with some tweaks from Guus Houtzager.</p>
4965     <p>Many people have reported bugs, made useful suggestions and helped
4966     with testing; see the ChangeLog and the mail lists.</p>
4967     <p>Your name could appear here in the next version!</p>
4968     <p>
4969     <a href="#__index__"><small>Back to Top</small></a>
4970     </p>
4971     <hr />
4972     <h1><a name="license">License</a></h1>
4973     <p>This program is free software; you can redistribute it and/or modify it
4974     under the terms of the GNU General Public License as published by the
4975     Free Software Foundation; either version 2 of the License, or (at your
4976     option) any later version.</p>
4977     <p>This program is distributed in the hope that it will be useful,
4978     but WITHOUT ANY WARRANTY; without even the implied warranty of
4979     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
4980     General Public License for more details.</p>
4981     <p>You should have received a copy of the GNU General Public License in the
4982     LICENSE file along with this program; if not, write to the Free Software
4983     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.</p>
4984     <p><a href="#__index__"><small>Back to Top</small></a></p>
4985     <table border="0" width="100%" cellspacing="0" cellpadding="3">
4986     <tr><td class="block" style="background-color: #cccccc" valign="middle">
4987     <big><strong><span class="block">&nbsp;BackupPC</span></strong></big>
4988     </td></tr>
4989     </table>
4990    
4991     </body>
4992    
4993     </html>

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