NAME¶

BackupPC Introduction¶

Overview¶

•

A clever pooling scheme minimizes disk storage and disk I/O. Identical files across multiple backups of the same or different PC are stored only once (using hard links), resulting in substantial savings in disk storage and disk writes.

•

Optional compression provides additional reductions in storage (around 40%). The CPU impact of compression is low since only new files (those not already in the pool) need to be compressed.

•

A powerful http/cgi user interface allows administrators to view the current status, edit configuration, add/delete hosts, view log files, and allows users to initiate and cancel backups and browse and restore files from backups.

•

The http/cgi user interface has internationalization (i18n) support, currently providing English, French, German, Spanish, Italian, Dutch, Polish, Portuguese-Brazilian and Chinese

•

No client-side software is needed. On WinXX the standard smb protocol is used to extract backup data. On linux, unix or MacOSX clients, rsync, tar (over ssh/rsh/nfs) or ftp is used to extract backup data. Alternatively, rsync can also be used on WinXX (using cygwin), and Samba could be installed on the linux or unix client to provide smb shares).

•

Flexible restore options. Single files can be downloaded from any backup directly from the CGI interface. Zip or Tar archives for selected files or directories from any backup can also be downloaded from the CGI interface. Finally, direct restore to the client machine (using smb or tar) for selected files or directories is also supported from the CGI interface.

•

BackupPC supports mobile environments where laptops are only intermittently connected to the network and have dynamic IP addresses (DHCP). Configuration settings allow machines connected via slower WAN connections (eg: dial up, DSL, cable) to not be backed up, even if they use the same fixed or dynamic IP address as when they are connected directly to the LAN.

•

Flexible configuration parameters allow multiple backups to be performed in parallel, specification of which shares to backup, which directories to backup or not backup, various schedules for full and incremental backups, schedules for email reminders to users and so on. Configuration parameters can be set system-wide or also on a per-PC basis.

•

Users are sent periodic email reminders if their PC has not recently been backed up. Email content, timing and policies are configurable.

•

BackupPC is Open Source software hosted by SourceForge.

Backup basics¶

Full Backup

A full backup is a complete backup of a share. BackupPC can be configured to do a full backup at a regular interval (typically weekly). BackupPC can be configured to keep a certain number of full backups. Exponential expiry is also supported, allowing full backups with various vintages to be kept (for example, a settable number of most recent weekly fulls, plus a settable number of older fulls that are 2, 4, 8, or 16 weeks apart).

Incremental Backup

An incremental backup is a backup of files that have changed since the last successful full or incremental backup. Starting in BackupPC 3.0 multi-level incrementals are supported. A full backup has level 0. A new incremental of level N will backup all files that have changed since the most recent backup of a lower level. $Conf{IncrLevels} is used to specify the level of each successive incremental. The default value is all level 1, which makes the behavior the same as earlier versions of BackupPC: each incremental will back up all the files that changed since the last full (level 0).

 

For SMB and tar, BackupPC uses the modification time (mtime) to determine which files have changed since the last lower-level backup. That means SMB and tar incrementals are not able to detect deleted files, renamed files or new files whose modification time is prior to the last lower-level backup.

 

Rsync is more clever: any files whose attributes have changed (ie: uid, gid, mtime, modes, size) since the last full are backed up. Deleted, new files and renamed files are detected by Rsync incrementals.

 

BackupPC can also be configured to keep a certain number of incremental backups, and to keep a smaller number of very old incremental backups. If multi-level incrementals are specified then it is likely that more incrementals will need to be kept since lower-level incrementals (and the full backup) are needed to reconstruct a higher-level incremental.

 

BackupPC "fills-in" incremental backups when browsing or restoring, based on the levels of each backup, giving every backup a "full" appearance. This makes browsing and restoring backups much easier: you can restore from any one backup independent of whether it was an incremental or full.

Partial Backup

When a full backup fails or is canceled, and some files have already been backed up, BackupPC keeps a partial backup containing just the files that were backed up successfully. The partial backup is removed when the next successful backup completes, or if another full backup fails resulting in a newer partial backup. A failed full backup that has not backed up any files, or any failed incremental backup, is removed; no partial backup is saved in these cases.

 

The partial backup may be browsed or used to restore files just like a successful full or incremental backup.

 

With the rsync transfer method the partial backup is used to resume the next full backup, avoiding the need to retransfer the file data already in the partial backup.

Identical Files

BackupPC pools identical files using hardlinks. By "identical files" we mean files with identical contents, not necessary the same permissions, ownership or modification time. Two files might have different permissions, ownership, or modification time but will still be pooled whenever the contents are identical. This is possible since BackupPC stores the file meta-data (permissions, ownership, and modification time) separately from the file contents.

Backup Policy

Based on your site's requirements you need to decide what your backup policy is. BackupPC is not designed to provide exact re-imaging of failed disks. See Limitations for more information. However, the addition of tar transport for linux/unix clients, plus full support for special file types and unix attributes in v1.4.0 likely means an exact image of a linux/unix file system can be made.

 

BackupPC saves backups onto disk. Because of pooling you can relatively economically keep several weeks of old backups.

 

At some sites the disk-based backup will be adequate, without a secondary tape backup. This system is robust to any single failure: if a client disk fails or loses files, the BackupPC server can be used to restore files. If the server disk fails, BackupPC can be restarted on a fresh file system, and create new backups from the clients. The chance of the server disk failing can be made very small by spending more money on increasingly better RAID systems. However, there is still the risk of catastrophic events like fires or earthquakes that can destroy both the BackupPC server and the clients it is backing up if they are physically nearby.

 

Some sites might choose to do periodic backups to tape or cd/dvd. This backup can be done perhaps weekly using the archive function of BackupPC.

 

Other users have reported success with removable disks to rotate the BackupPC data drives, or using rsync to mirror the BackupPC data pool offsite.

Resources¶

BackupPC home page

The BackupPC Open Source project is hosted on SourceForge. The home page can be found at:

 

    http://backuppc.sourceforge.net
    

 

This page has links to the current documentation, the SourceForge project page and general information.

SourceForge project

The SourceForge project page is at:

 

    http://sourceforge.net/projects/backuppc
    

 

This page has links to the current releases of BackupPC.

BackupPC Wiki

BackupPC has a Wiki at <http://backuppc.wiki.sourceforge.net>. Everyone is encouraged to contribute to the Wiki. Anyone with a SourceForge account can edit the Wiki.

 

The old FAQ is at <http://backuppc.sourceforge.net/faq>, but is deprecated in favor of the Wiki.

Mailing lists

Three BackupPC mailing lists exist for announcements (backuppc-announce), developers (backuppc-devel), and a general user list for support, asking questions or any other topic relevant to BackupPC (backuppc-users).

 

The lists are archived on SourceForge and Gmane. The SourceForge lists are not always up to date and the searching is limited, so Gmane is a good alternative. See:

 

    http://news.gmane.org/index.php?prefix=gmane.comp.sysutils.backup.backuppc
    http://sourceforge.net/mailarchive/forum.php?forum=backuppc-users
    

 

You can subscribe to these lists by visiting:

 

    http://lists.sourceforge.net/lists/listinfo/backuppc-announce
    http://lists.sourceforge.net/lists/listinfo/backuppc-users
    http://lists.sourceforge.net/lists/listinfo/backuppc-devel
    

 

The backuppc-announce list is moderated and is used only for important announcements (eg: new versions). It is low traffic. You only need to subscribe to one of backuppc-announce and backuppc-users: backuppc-users also receives any messages on backuppc-announce.

 

The backuppc-devel list is only for developers who are working on BackupPC. Do not post questions or support requests there. But detailed technical discussions should happen on this list.

 

To post a message to the backuppc-users list, send an email to

 

    backuppc-users@lists.sourceforge.net
    

 

Do not send subscription requests to this address!

Other Programs of Interest

If you want to mirror linux or unix files or directories to a remote server you should use rsync, <http://rsync.samba.org>. BackupPC uses rsync as a transport mechanism; if you are already an rsync user you can think of BackupPC as adding efficient storage (compression and pooling) and a convenient user interface to rsync.

 

Two popular open source packages that do tape backup are Amanda (<http://www.amanda.org>) and Bacula (<http://www.bacula.org>). These packages can be used as complete solutions, or also as back ends to BackupPC to backup the BackupPC server data to tape.

 

Various programs and scripts use rsync to provide hardlinked backups. See, for example, Mike Rubel's site (<http://www.mikerubel.org/computers/rsync_snapshots>), JW Schultz's dirvish (<http://www.dirvish.org/>), Ben Escoto's rdiff-backup (http://www.nongnu.org/rdiff-backup <http://www.nongnu.org/rdiff-backup>), and John Bowman's rlbackup (<http://www.math.ualberta.ca/imaging/rlbackup>).

 

Unison is a utility that can do two-way, interactive, synchronization. See <http://freshmeat.net/projects/unison>. An external wrapper around rsync that maintains transfer data to enable two-way synchronization is drsync; see <http://freshmeat.net/projects/drsync>.

 

BackupPC provides many additional features, such as compressed storage, hardlinking any matching files (rather than just files with the same name), and storing special files without root privileges. But these other programs provide simple, effective and fast solutions and are definitely worthy of consideration.

Road map¶

You can help¶

Installing BackupPC¶

Requirements¶

•

A linux, solaris, or unix based server with a substantial amount of free disk space (see the next section for what that means). The CPU and disk performance on this server will determine how many simultaneous backups you can run. You should be able to run 4-8 simultaneous backups on a moderately configured server.

 

Several users have reported significantly better performance using reiserfs compared to ext3 for the BackupPC data file system. It is also recommended you consider either an LVM or RAID setup (either in HW or SW; eg: 3Ware RAID10 or RAID5) so that you can expand the file system as necessary.

 

When BackupPC starts with an empty pool, all the backup data will be written to the pool on disk. After more backups are done, a higher percentage of incoming files will already be in the pool. BackupPC is able to avoid writing to disk new files that are already in the pool. So over time disk writes will reduce significantly (by perhaps a factor of 20 or more), since eventually 95% or more of incoming backup files are typically in the pool. Disk reads from the pool are still needed to do file compares to verify files are an exact match. So, with a mature pool, if a relatively fast client generates data at say 1MB/sec, and you run 4 simultaneous backups, there will be an average server disk load of about 4MB/sec reads and 0.2MB/sec writes (assuming 95% of the incoming files are in the pool). These rates will be perhaps 40% lower if compression is on.

•

Perl version 5.8.0 or later. If you don't have perl, please see <http://www.cpan.org>.

•

Perl modules Compress::Zlib, Archive::Zip and File::RsyncP. Try "perldoc Compress::Zlib" and "perldoc Archive::Zip" to see if you have these modules. If not, fetch them from <http://www.cpan.org> and see the instructions below for how to build and install them.

 

The File::RsyncP module is available from <http://perlrsync.sourceforge.net> or CPAN. You'll need to install the File::RsyncP module if you want to use Rsync as a transport method.

•

If you are using smb to backup WinXX machines you need smbclient and nmblookup from the samba package. You will also need nmblookup if you are backing up linux/unix DHCP machines. See <http://www.samba.org>. Samba versions 3.x are stable and now recommended instead of 2.x.

 

See <http://www.samba.org> for source and binaries. It's pretty easy to fetch and compile samba, and just grab smbclient and nmblookup, without doing the installation. Alternatively, <http://www.samba.org> has binary distributions for most platforms.

•

If you are using tar to backup linux/unix machines, those machines should have version 1.13.7 at a minimum, with version 1.13.20 or higher recommended. Use "tar --version" to check your version. Various GNU mirrors have the newest versions of tar; see <http://www.gnu.org/software/tar/>.

•

If you are using rsync to backup linux/unix machines you should have version 2.6.3 or higher on each client machine. See <http://rsync.samba.org>. Use "rsync --version" to check your version.

 

For BackupPC to use Rsync you will also need to install the perl File::RsyncP module, which is available from <http://perlrsync.sourceforge.net>. Version 0.68 or later is required.

•

The Apache web server, see <http://www.apache.org>, preferably built with mod_perl support.

What type of storage space do I need?¶

How much disk space do I need?¶

Step 1: Getting BackupPC¶

    apt-get install backuppc

Step 2: Installing the distribution¶

Compress::Zlib

To enable compression, you will need to install Compress::Zlib from <http://www.cpan.org>. You can run "perldoc Compress::Zlib" to see if this module is installed.

Archive::Zip

To support restore via Zip archives you will need to install Archive::Zip, also from <http://www.cpan.org>. You can run "perldoc Archive::Zip" to see if this module is installed.

XML::RSS

To support the RSS feature you will need to install XML::RSS, also from <http://www.cpan.org>. There is not need to install this module if you don't plan on using RSS. You can run "perldoc XML::RSS" to see if this module is installed.

File::RsyncP

To use rsync and rsyncd with BackupPC you will need to install File::RsyncP. You can run "perldoc File::RsyncP" to see if this module is installed. File::RsyncP is available from <http://perlrsync.sourceforge.net>. Version 0.68 or later is required.

File::Listing, Net::FTP, Net::FTP::RetrHandle, Net::FTP::AutoReconnect

To use ftp with BackupPC you will need four libraries, but actually need to install only File::Listing from <http://www.cpan.org>. You can run "perldoc File::Listing" to see if this module is installed. Net::FTP is a standard module. Net::FTP::RetrHandle and Net::FTP::AutoReconnect included in BackupPC distribution.

    tar zxvf Archive-Zip-1.26.tar.gz
    cd Archive-Zip-1.26
    perl Makefile.PL
    make
    make test
    make install

    tar zxf BackupPC-3.2.1.tar.gz
    cd BackupPC-3.2.1
    perl configure.pl

    BackupPC-3.2.1plN.diff

     # fetch BackupPC-3.2.1.tar.gz
     # fetch BackupPC-3.2.1pl2.diff
     tar zxf BackupPC-3.2.1.tar.gz
     cd BackupPC-3.2.1
     patch -p0 < ../BackupPC-3.2.1pl2.diff
     perl configure.pl

    perldoc configure.pl

BackupPC User

It is best if BackupPC runs as a special user, eg backuppc, that has limited privileges. It is preferred that backuppc belongs to a system administrator group so that sys admin members can browse BackupPC files, edit the configuration files and so on. Although configurable, the default settings leave group read permission on pool files, so make sure the BackupPC user's group is chosen restrictively.

 

On this installation, this is __BACKUPPCUSER__.

 

For security purposes you might choose to configure the BackupPC user with the shell set to /bin/false. Since you might need to run some BackupPC programs as the BackupPC user for testing purposes, you can use the -s option to su to explicitly run a shell, eg:

 

    su -s /bin/bash __BACKUPPCUSER__
    

 

Depending upon your configuration you might also need the -l option.

Data Directory

You need to decide where to put the data directory, below which all the BackupPC data is stored. This needs to be a big file system.

 

On this installation, this is __TOPDIR__.

Install Directory

You should decide where the BackupPC scripts, libraries and documentation should be installed, eg: /usr/local/BackupPC.

 

On this installation, this is __INSTALLDIR__.

CGI bin Directory

You should decide where the BackupPC CGI script resides. This will usually be below Apache's cgi-bin directory.

 

It is also possible to use a different directory and use Apache's ``<Directory>'' directive to specifiy that location. See the Apache HTTP Server documentation for additional information.

 

On this installation, this is __CGIDIR__.

Apache image Directory

A directory where BackupPC's images are stored so that Apache can serve them. You should ensure this directory is readable by Apache and create a symlink to this directory from the BackupPC CGI bin Directory.

Config and Log Directories

In this installation the configuration and log directories are located in the following locations:

 

    __CONFDIR__/config.pl    main config file
    __CONFDIR__/hosts        hosts file
    __CONFDIR__/pc/HOST.pl   per-pc config file
    __LOGDIR__/BackupPC      log files, pid, status
    

 

The configure.pl script doesn't prompt for these locations but they can be set for new installations using command-line options.

Step 3: Setting up config.pl¶

Step 4: Setting up the hosts file¶

•

Upon startup.

•

When BackupPC is sent a HUP (-1) signal. Assuming you installed the init.d script, you can also do this with "/etc/init.d/backuppc reload".

•

When the modification time of the hosts file changes. BackupPC checks the modification time once during each regular wakeup.

Host name

This is typically the host name or NetBios name of the client machine and should be in lower case. The host name can contain spaces (escape with a backslash), but it is not recommended.

 

Please read the section How BackupPC Finds Hosts.

 

In certain cases you might want several distinct clients to refer to the same physical machine. For example, you might have a database you want to backup, and you want to bracket the backup of the database with shutdown/restart using $Conf{DumpPreUserCmd} and $Conf{DumpPostUserCmd}. But you also want to backup the rest of the machine while the database is still running. In the case you can specify two different clients in the host file, using any mnemonic name (eg: myhost_mysql and myhost), and use $Conf{ClientNameAlias} in myhost_mysql's config.pl to specify the real host name of the machine.

DHCP flag

Starting with v2.0.0 the way hosts are discovered has changed and now in most cases you should specify 0 for the DHCP flag, even if the host has a dynamically assigned IP address. Please read the section How BackupPC Finds Hosts to understand whether you need to set the DHCP flag.

 

You only need to set DHCP to 1 if your client machine doesn't respond to the NetBios multicast request:

 

    nmblookup myHost
    

 

but does respond to a request directed to its IP address:

 

    nmblookup -A W.X.Y.Z
    

 

If you do set DHCP to 1 on any client you will need to specify the range of DHCP addresses to search is specified in $Conf{DHCPAddressRanges}.

 

Note also that the $Conf{ClientNameAlias} feature does not work for clients with DHCP set to 1.

User name

This should be the unix login/email name of the user who "owns" or uses this machine. This is the user who will be sent email about this machine, and this user will have permission to stop/start/browse/restore backups for this host. Leave this blank if no specific person should receive email or be allowed to stop/start/browse/restore backups for this host. Administrators will still have full permissions.

More users

Additional user names, separate by commas and with no white space, can be specified. These users will also have full permission in the CGI interface to stop/start/browse/restore backups for this host. These users will not be sent email about this host.

    host        dhcp    user      moreUsers
    farside     0       craig     jim,dave
    larson      1       gary      andy

Step 5: Client Setup¶

WinXX

One setup for WinXX clients is to set $Conf{XferMethod} to "smb". Actually, rsyncd is the better method for WinXX if you are prepared to run rsync/cygwin on your WinXX client.

 

If you want to use rsyncd for WinXX clients you can find a pre-packaged zip file on <http://backuppc.sourceforge.net>. The package is called cygwin-rsync. It contains rsync.exe, template setup files and the minimal set of cygwin libraries for everything to run. The README file contains instructions for running rsync as a service, so it starts automatically everytime you boot your machine. If you use rsync to backup WinXX machines, be sure to set $Conf{ClientCharset} correctly (eg: 'cp1252') so that the WinXX file name encoding is correctly converted to utf8.

 

Otherwise, to use SMB, you can either create shares for the data you want to backup or your can use the existing C$ share. To create a new share, open "My Computer", right click on the drive (eg: C), and select "Sharing..." (or select "Properties" and select the "Sharing" tab). In this dialog box you can enable sharing, select the share name and permissions.

 

All Windows NT based OS (NT, 2000, XP Pro), are configured by default to share the entire C drive as C$. This is a special share used for various administration functions, one of which is to grant access to backup operators. All you need to do is create a new domain user, specifically for backup. Then add the new backup user to the built in "Backup Operators" group. You now have backup capability for any directory on any computer in the domain in one easy step. This avoids using administrator accounts and only grants permission to do exactly what you want for the given user, i.e.: backup. Also, for additional security, you may wish to deny the ability for this user to logon to computers in the default domain policy.

 

If this machine uses DHCP you will also need to make sure the NetBios name is set. Go to Control Panel|System|Network Identification (on Win2K) or Control Panel|System|Computer Name (on WinXP). Also, you should go to Control Panel|Network Connections|Local Area Connection|Properties|Internet Protocol (TCP/IP)|Properties|Advanced|WINS and verify that NetBios is not disabled.

 

The relevant configuration settings are $Conf{SmbShareName}, $Conf{SmbShareUserName}, $Conf{SmbSharePasswd}, $Conf{SmbClientPath}, $Conf{SmbClientFullCmd}, $Conf{SmbClientIncrCmd} and $Conf{SmbClientRestoreCmd}.

 

BackupPC needs to know the smb share user name and password for a client machine that uses smb. The user name is specified in $Conf{SmbShareUserName}. There are four ways to tell BackupPC the smb share password:

    [global]
        unix charset = UTF8

Linux/Unix

The preferred setup for linux/unix clients is to set $Conf{XferMethod} to "rsync", "rsyncd" or "tar".

 

You can use either rsync, smb, or tar for linux/unix machines. Smb requires that the Samba server (smbd) be run to provide the shares. Since the smb protocol can't represent special files like symbolic links and fifos, tar and rsync are the better transport methods for linux/unix machines. (In fact, by default samba makes symbolic links look like the file or directory that they point to, so you could get an infinite loop if a symbolic link points to the current or parent directory. If you really need to use Samba shares for linux/unix backups you should turn off the "follow symlinks" samba config setting. See the smb.conf manual page.)

 

The requirements for each Xfer Method are:

MacOSX

In general this should be similar to Linux/Unix machines. In versions 10.4 and later, the native MacOSX tar works, and also supports resource forks. xtar is another option, and rsync works too (although the MacOSX-supplied rsync has an extension for extended attributes that is not compatible with standard rsync).

SSH Setup

SSH is a secure way to run tar or rsync on a backup client to extract the data. SSH provides strong authentication and encryption of the network data.

 

Note that if you run rsyncd (rsync daemon), ssh is not used. In this case, rsyncd provides its own authentication, but there is no encryption of network data. If you want encryption of network data you can use ssh to create a tunnel, or use a program like stunnel.

 

Setup instructions for ssh can be found at <http://backuppc.sourceforge.net/faq/ssh.html> or on the Wiki.

Clients that use DHCP

If a client machine uses DHCP BackupPC needs some way to find the IP address given the host name. One alternative is to set dhcp to 1 in the hosts file, and BackupPC will search a pool of IP addresses looking for hosts. More efficiently, it is better to set dhcp = 0 and provide a mechanism for BackupPC to find the IP address given the host name.

 

For WinXX machines BackupPC uses the NetBios name server to determine the IP address given the host name. For unix machines you can run nmbd (the NetBios name server) from the Samba distribution so that the machine responds to a NetBios name request. See the manual page and Samba documentation for more information.

 

Alternatively, you can set $Conf{NmbLookupFindHostCmd} to any command that returns the IP address given the host name.

 

Please read the section How BackupPC Finds Hosts for more details.

Step 6: Running BackupPC¶

    /etc/init.d/backuppc start

     __INSTALLDIR__/bin/BackupPC -d

Step 7: Talking to BackupPC¶

    su __BACKUPPCUSER__

    su -s /bin/bash __BACKUPPCUSER__

    __INSTALLDIR__/bin/BackupPC_serverMesg status info
    __INSTALLDIR__/bin/BackupPC_serverMesg status jobs
    __INSTALLDIR__/bin/BackupPC_serverMesg status hosts

    __INSTALLDIR__/bin/BackupPC_serverMesg backup all

Step 8: Checking email delivery¶

    su __BACKUPPCUSER__
    __INSTALLDIR__/bin/BackupPC_sendEmail -u MYNAME@MYDOMAIN.COM

    __INSTALLDIR__/bin/BackupPC_sendEmail -c

Step 9: CGI interface¶

    httpd -l | egrep mod_perl

Standard Setup

The CGI interface should have been installed by the configure.pl script in __CGIDIR__/BackupPC_Admin. BackupPC_Admin should have been installed as setuid to the BackupPC user (__BACKUPPCUSER__), in addition to user and group execute permission.

 

You should be very careful about permissions on BackupPC_Admin and the directory __CGIDIR__: it is important that normal users cannot directly execute or change BackupPC_Admin, otherwise they can access backup files for any PC. You might need to change the group ownership of BackupPC_Admin to a group that Apache belongs to so that Apache can execute it (don't add "other" execute permission!). The permissions should look like this:

 

    ls -l __CGIDIR__/BackupPC_Admin
    -swxr-x---    1 __BACKUPPCUSER__   web      82406 Jun 17 22:58 __CGIDIR__/BackupPC_Admin
    

 

The setuid script won't work unless perl on your machine was installed with setuid emulation. This is likely the problem if you get an error saying such as "Wrong user: my userid is 25, instead of 150", meaning the script is running as the httpd user, not the BackupPC user. This is because setuid scripts are disabled by the kernel in most flavors of unix and linux.

 

To see if your perl has setuid emulation, see if there is a program called sperl5.8.0 (or sperl5.8.2 etc, based on your perl version) in the place where perl is installed. If you can't find this program, then you have two options: rebuild and reinstall perl with the setuid emulation turned on (answer "y" to the question "Do you want to do setuid/setgid emulation?" when you run perl's configure script), or switch to the mod_perl alternative for the CGI script (which doesn't need setuid to work).

Mod_perl Setup

The advantage of the mod_perl setup is that no setuid script is needed, and there is a huge performance advantage. Not only does all the perl code need to be parsed just once, the config.pl and hosts files, plus the connection to the BackupPC server are cached between requests. The typical speedup is around 15 times.

 

To use mod_perl you need to run Apache as user __BACKUPPCUSER__. If you need to run multiple Apache's for different services then you need to create multiple top-level Apache directories, each with their own config file. You can make copies of /etc/init.d/httpd and use the -d option to httpd to point each http to a different top-level directory. Or you can use the -f option to explicitly point to the config file. Multiple Apache's will run on different Ports (eg: 80 is standard, 8080 is a typical alternative port accessed via http://yourhost.com:8080).

 

Inside BackupPC's Apache http.conf file you should check the settings for ServerRoot, DocumentRoot, User, Group, and Port. See http://httpd.apache.org/docs/server-wide.html <http://httpd.apache.org/docs/server-wide.html> for more details.

 

For mod_perl, BackupPC_Admin should not have setuid permission, so you should turn it off:

 

    chmod u-s __CGIDIR__/BackupPC_Admin
    

 

To tell Apache to use mod_perl to execute BackupPC_Admin, add this to Apache's 1.x httpd.conf file:

 

    <IfModule mod_perl.c>
        PerlModule Apache::Registry
        PerlTaintCheck On
        <Location /cgi-bin/BackupPC/BackupPC_Admin>   # <--- change path as needed
           SetHandler perl-script
           PerlHandler Apache::Registry
           Options ExecCGI
           PerlSendHeader On
        </Location>
    </IfModule>
    

 

Apache 2.0.44 with Perl 5.8.0 on RedHat 7.1, Don Silvia reports that this works (with tweaks from Michael Tuzi):

 

    LoadModule perl_module modules/mod_perl.so
    PerlModule Apache2
    <Directory /path/to/cgi/>
        SetHandler perl-script
        PerlResponseHandler ModPerl::Registry
        PerlOptions +ParseHeaders
        Options +ExecCGI
        Order deny,allow
        Deny from all
        Allow from 192.168.0  
        AuthName "Backup Admin"
        AuthType Basic
        AuthUserFile /path/to/user_file
        Require valid-user
    </Directory>
    

 

There are other optimizations and options with mod_perl. For example, you can tell mod_perl to preload various perl modules, which saves memory compared to loading separate copies in every Apache process after they are forked. See Stas's definitive mod_perl guide at <http://perl.apache.org/guide>.

    AuthGroupFile /etc/httpd/conf/group    # <--- change path as needed
    AuthUserFile /etc/http/conf/passwd     # <--- change path as needed
    AuthType basic
    AuthName "access"
    require valid-user

    LoadModule auth_ldap_module   modules/auth_ldap.so
    AddModule auth_ldap.c
    # cgi-bin - auth via LDAP (for BackupPC)
    <Location /cgi-binBackupPC/BackupPC_Admin>    # <--- change path as needed
      AuthType Basic
      AuthName "BackupPC login"
      # replace MYDOMAIN, PORT, ORG and CO as needed
      AuthLDAPURL ldap://ldap.MYDOMAIN.com:PORT/o=ORG,c=CO?uid?sub?(objectClass=*)
      require valid-user
    </Location>

    <Location /cgi-bin/BackupPC/BackupPC_Admin>   # <--- change path as needed
        Setenv REMOTE_USER www
    </Location>

How BackupPC Finds Hosts¶

•

First DNS is used to lookup the IP address given the client's name using perl's gethostbyname() function. This should succeed for machines that have fixed IP addresses that are known via DNS. You can manually see whether a given host have a DNS entry according to perl's gethostbyname function with this command:

 

    perl -e 'print(gethostbyname("myhost") ? "ok\n" : "not found\n");'
    

•

If gethostbyname() fails, BackupPC then attempts a NetBios multicast to find the host. Provided your client machine is configured properly, it should respond to this NetBios multicast request. Specifically, BackupPC runs a command of this form:

 

    nmblookup myhost
    

 

If this fails you will see output like:

 

    querying myhost on 10.10.255.255
    name_query failed to find name myhost
    

 

If it is successful you will see output like:

 

    querying myhost on 10.10.255.255
    10.10.1.73 myhost<00>
    

 

Depending on your netmask you might need to specify the -B option to nmblookup. For example:

 

    nmblookup -B 10.10.1.255 myhost
    

 

If necessary, experiment with the nmblookup command which will return the IP address of the client given its name. Then update $Conf{NmbLookupFindHostCmd} with any necessary options to nmblookup.

•

A DHCP address pool ($Conf{DHCPAddressRanges}) needs to be specified. BackupPC will check the NetBIOS name of each machine in the range using a command of the form:

 

    nmblookup -A W.X.Y.Z
    

 

where W.X.Y.Z is each candidate address from $Conf{DHCPAddressRanges}. Any host that has a valid NetBIOS name returned by this command (ie: matching an entry in the hosts file) will be backed up. You can modify the specific nmblookup command if necessary via $Conf{NmbLookupCmd}.

•

You only need to use this DHCP feature if your client machine doesn't respond to the NetBios multicast request:

 

    nmblookup myHost
    

 

but does respond to a request directed to its IP address:

 

    nmblookup -A W.X.Y.Z
    

Other installation topics¶

Removing a client

If there is a machine that no longer needs to be backed up (eg: a retired machine) you have two choices. First, you can keep the backups accessible and browsable, but disable all new backups. Alternatively, you can completely remove the client and all its backups.

 

To disable backups for a client $Conf{BackupsDisable} can be set to two different values in that client's per-PC config.pl file:

Copying the pool

If the pool disk requirements grow you might need to copy the entire data directory to a new (bigger) file system. Hopefully you are lucky enough to avoid this by having the data directory on a RAID file system or LVM that allows the capacity to be grown in place by adding disks.

 

The backup data directories contain large numbers of hardlinks. If you try to copy the pool the target directory will occupy a lot more space if the hardlinks aren't re-established.

 

The best way to copy a pool file system, if possible, is by copying the raw device at the block level (eg: using dd). Application level programs that understand hardlinks include the GNU cp program with the -a option and rsync -H. However, the large number of hardlinks in the pool will make the memory usage large and the copy very slow. Don't forget to stop BackupPC while the copy runs.

 

Starting in 3.0.0 a new script bin/BackupPC_tarPCCopy can be used to assist the copy process. Given one or more pc paths (eg: TOPDIR/pc/HOST or TOPDIR/pc/HOST/nnn), BackupPC_tarPCCopy creates a tar archive with all the hardlinks pointing to ../cpool/.... Any files not hardlinked (eg: backups, LOG etc) are included verbatim.

 

You will need to specify the -P option to tar when you extract the archive generated by BackupPC_tarPCCopy since the hardlink targets are outside of the directory being extracted.

 

To copy a complete store (ie: __TOPDIR__) using BackupPC_tarPCCopy you should:

Fixing installation problems¶

Restore functions¶

CGI restore options¶

Option 1: Direct Restore

With this option the selected files and directories are restored directly back onto the host, by default in their original location. Any old files with the same name will be overwritten, so use caution. You can optionally change the target host name, target share name, and target path prefix for the restore, allowing you to restore the files to a different location.

 

Once you select "Start Restore" you will be prompted one last time with a summary of the exact source and target files and directories before you commit. When you give the final go ahead the restore operation will be queued like a normal backup job, meaning that it will be deferred if there is a backup currently running for that host. When the restore job is run, smbclient, tar, rsync or rsyncd is used (depending upon $Conf{XferMethod}) to actually restore the files. Sorry, there is currently no option to cancel a restore that has been started. Currently ftp restores are not fully implemented.

 

A record of the restore request, including the result and list of files and directories, is kept. It can be browsed from the host's home page. $Conf{RestoreInfoKeepCnt} specifies how many old restore status files to keep.

 

Note that for direct restore to work, the $Conf{XferMethod} must be able to write to the client. For example, that means an SMB share for smbclient needs to be writable, and the rsyncd module needs "read only" set to "false". This creates additional security risks. If you only create read-only SMB shares (which is a good idea), then the direct restore will fail. You can disable the direct restore option by setting $Conf{SmbClientRestoreCmd}, $Conf{TarClientRestoreCmd} and $Conf{RsyncRestoreArgs} to undef.

Option 2: Download Zip archive

With this option a zip file containing the selected files and directories is downloaded. The zip file can then be unpacked or individual files extracted as necessary on the host machine. The compression level can be specified. A value of 0 turns off compression.

 

When you select "Download Zip File" you should be prompted where to save the restore.zip file.

 

BackupPC does not consider downloading a zip file as an actual restore operation, so the details are not saved for later browsing as in the first case. However, a mention that a zip file was downloaded by a particular user, and a list of the files, does appear in BackupPC's log file.

Option 3: Download Tar archive

This is identical to the previous option, except a tar file is downloaded rather than a zip file (and there is currently no compression option).

Command-line restore options¶

BackupPC_zcat

For each file name argument it inflates (uncompresses) the file and writes it to stdout. To use BackupPC_zcat you could give it the full file name, eg:

 

    __INSTALLDIR__/bin/BackupPC_zcat __TOPDIR__/pc/host/5/fc/fcraig/fexample.txt > example.txt
    

 

It's your responsibility to make sure the file is really compressed: BackupPC_zcat doesn't check which backup the requested file is from. BackupPC_zcat returns a non-zero status if it fails to uncompress a file.

BackupPC_tarCreate

BackupPC_tarCreate creates a tar file for any files or directories in a particular backup. Merging of incrementals is done automatically, so you don't need to worry about whether certain files appear in the incremental or full backup.

 

The usage is:

 

    BackupPC_tarCreate [options] files/directories...
    Required options:
       -h host         host from which the tar archive is created
       -n dumpNum      dump number from which the tar archive is created
                       A negative number means relative to the end (eg -1
                       means the most recent dump, -2 2nd most recent etc).
       -s shareName    share name from which the tar archive is created
  
    Other options:
       -t              print summary totals
       -r pathRemove   path prefix that will be replaced with pathAdd
       -p pathAdd      new path prefix
       -b BLOCKS       BLOCKS x 512 bytes per record (default 20; same as tar)
       -w writeBufSz   write buffer size (default 1048576 = 1MB)
       -e charset      charset for encoding file names (default: value of
                       $Conf{ClientCharset} when backup was done)
       -l              just print a file listing; don't generate an archive
       -L              just print a detailed file listing; don't generate an archive
    

 

The command-line files and directories are relative to the specified shareName. The tar file is written to stdout.

 

The -h, -n and -s options specify which dump is used to generate the tar archive. The -r and -p options can be used to relocate the paths in the tar archive so extracted files can be placed in a location different from their original location.

BackupPC_zipCreate

BackupPC_zipCreate creates a zip file for any files or directories in a particular backup. Merging of incrementals is done automatically, so you don't need to worry about whether certain files appear in the incremental or full backup.

 

The usage is:

 

    BackupPC_zipCreate [options] files/directories...
    Required options:
       -h host         host from which the zip archive is created
       -n dumpNum      dump number from which the tar archive is created
                       A negative number means relative to the end (eg -1
                       means the most recent dump, -2 2nd most recent etc).
       -s shareName    share name from which the zip archive is created
  
    Other options:
       -t              print summary totals
       -r pathRemove   path prefix that will be replaced with pathAdd
       -p pathAdd      new path prefix
       -c level        compression level (default is 0, no compression)
       -e charset      charset for encoding file names (default: cp1252)
    

 

The command-line files and directories are relative to the specified shareName. The zip file is written to stdout. The -h, -n and -s options specify which dump is used to generate the zip archive. The -r and -p options can be used to relocate the paths in the zip archive so extracted files can be placed in a location different from their original location.

Archive functions¶

Configuring an Archive Host¶

     __INSTALLDIR__/bin/BackupPC_archiveHost

Starting an Archive¶

Starting an Archive from the command line¶

    BackupPC_archiveStart archiveHost userName hosts...

Other CGI Functions¶

Configuration and Host Editor¶

RSS¶

    http://localhost/cgi-bin/BackupPC/BackupPC_Admin?action=rss

BackupPC Design¶

Some design issues¶

Pooling common files

To quickly see if a file is already in the pool, an MD5 digest of the file length and contents is used as the file name in the pool. This can't guarantee a file is identical: it just reduces the search to often a single file or handful of files. A complete file comparison is always done to verify if two files are really the same.

 

Identical files on multiples backups are represented by hard links. Hardlinks are used so that identical files all refer to the same physical file on the server's disk. Also, hard links maintain reference counts so that BackupPC knows when to delete unused files from the pool.

 

For the computer-science majors among you, you can think of the pooling system used by BackupPC as just a chained hash table stored on a (big) file system.

The hashing function

There is a tradeoff between how much of file is used for the MD5 digest and the time taken comparing all the files that have the same hash.

 

Using the file length and just the first 4096 bytes of the file for the MD5 digest produces some repetitions. One example: with 900,000 unique files in the pool, this hash gives about 7,000 repeated files, and in the worst case 500 files have the same hash. That's not bad: we only have to do a single file compare 99.2% of the time. But in the worst case we have to compare as many as 500 files checking for a match.

 

With a modest increase in CPU time, if we use the file length and the first 256K of the file we now only have 500 repeated files and in the worst case around 20 files have the same hash. Furthermore, if we instead use the first and last 128K of the file (more specifically, the first and eighth 128K chunks for files larger than 1MB) we get only 300 repeated files and in the worst case around 20 files have the same hash.

 

Based on this experimentation, this is the hash function used by BackupPC. It is important that you don't change the hash function after files are already in the pool. Otherwise your pool will grow to twice the size until all the old backups (and all the old files with old hashes) eventually expire.

Compression

BackupPC supports compression. It uses the deflate and inflate methods in the Compress::Zlib module, which is based on the zlib compression library (see <http://www.gzip.org/zlib/>).

 

The $Conf{CompressLevel} setting specifies the compression level to use. Zero (0) means no compression. Compression levels can be from 1 (least cpu time, slightly worse compression) to 9 (most cpu time, slightly better compression). The recommended value is 3. Changing it to 5, for example, will take maybe 20% more cpu time and will get another 2-3% additional compression. Diminishing returns set in above 5. See the zlib documentation for more information about compression levels.

 

BackupPC implements compression with minimal CPU load. Rather than compressing every incoming backup file and then trying to match it against the pool, BackupPC computes the MD5 digest based on the uncompressed file, and matches against the candidate pool files by comparing each uncompressed pool file against the incoming backup file. Since inflating a file takes roughly a factor of 10 less CPU time than deflating there is a big saving in CPU time.

 

The combination of pooling common files and compression can yield a factor of 8 or more overall saving in backup storage.

BackupPC operation¶

1.

For each host and DHCP address backup requests are queued on the background command queue.

2.

For each PC, BackupPC_dump is forked. Several of these may be run in parallel, based on the configuration. First a ping is done to see if the machine is alive. If this is a DHCP address, nmblookup is run to get the netbios name, which is used as the host name. If DNS lookup fails, $Conf{NmbLookupFindHostCmd} is run to find the IP address from the host name. The file __TOPDIR__/pc/$host/backups is read to decide whether a full or incremental backup needs to be run. If no backup is scheduled, or the ping to $host fails, then BackupPC_dump exits.

 

The backup is done using the specified XferMethod. Either samba's smbclient or tar over ssh/rsh/nfs piped into BackupPC_tarExtract, or rsync over ssh/rsh is run, or rsyncd is connected to, with the incoming data extracted to __TOPDIR__/pc/$host/new. The XferMethod output is put into __TOPDIR__/pc/$host/XferLOG.

 

The letter in the XferLOG file shows the type of object, similar to the first letter of the modes displayed by ls -l:

 

    d -> directory
    l -> symbolic link
    b -> block special file
    c -> character special file
    p -> pipe file (fifo)
    nothing -> regular file
    

 

The words mean:

3.

For each complete, good, backup, BackupPC_link is run. To avoid race conditions as new files are linked into the pool area, only a single BackupPC_link program runs at a time and the rest are queued.

 

BackupPC_link reads the NewFileList written by BackupPC_dump and inspects each new file in the backup. It re-checks if there is a matching file in the pool (another BackupPC_link could have added the file since BackupPC_dump checked). If so, the file is removed and replaced by a hard link to the existing file. If the file is new, a hard link to the file is made in the pool area, so that this file is available for checking against each new file and new backup.

 

Then, if $Conf{IncrFill} is set (note that the default setting is off), for each incremental backup, hard links are made in the new backup to all files that were not extracted during the incremental backups. The means the incremental backup looks like a complete image of the PC (with the exception that files that were removed on the PC since the last full backup will still appear in the backup directory tree).

 

The CGI interface knows how to merge unfilled incremental backups will the most recent prior filled (full) backup, giving the incremental backups a filled appearance. The default for $Conf{IncrFill} is off, since there is no need to fill incremental backups. This saves some level of disk activity, since lots of extra hardlinks are no longer needed (and don't have to be deleted when the backup expires).

4.

BackupPC_trashClean is always run in the background to remove any expired backups. Every 5 minutes it wakes up and removes all the files in __TOPDIR__/trash.

 

Also, once each night, BackupPC_nightly is run to complete some additional administrative tasks, such as cleaning the pool. This involves removing any files in the pool that only have a single hard link (meaning no backups are using that file). Again, to avoid race conditions, BackupPC_nightly is only run when there are no BackupPC_link processes running. When BackupPC_nightly is run no new BackupPC_link jobs are started. If BackupPC_nightly takes too long to run, the settings $Conf{MaxBackupPCNightlyJobs} and $Conf{BackupPCNightlyPeriod} can be used to run several BackupPC_nightly processes in parallel, and to split its job over several nights.

Storage layout¶

__INSTALLDIR__

Perl scripts comprising BackupPC reside in __INSTALLDIR__/bin, libraries are in __INSTALLDIR__/lib and documentation is in __INSTALLDIR__/doc.

__CGIDIR__

The CGI script BackupPC_Admin resides in this cgi binary directory.

__CONFDIR__

All the configuration information resides below __CONFDIR__. This directory contains:

 

The directory __CONFDIR__ contains:

__LOGDIR__

The directory __LOGDIR__ (__TOPDIR__/log on pre-FHS versions of BackupPC) contains:

__TOPDIR__

All of BackupPC's data (PC backup images, logs, configuration information) is stored below this directory.

 

Below __TOPDIR__ are several directories:

Compressed file format¶

Rsync checksum caching¶

        '--checksum-seed=32761',

File name mangling¶

Special files¶

Attribute file format¶

•

File name length in perl's pack "w" format (variable length base 128).

•

File name.

•

The unix file type, mode, uid, gid and file size divided by 4GB and file size modulo 4GB (type mode uid gid sizeDiv4GB sizeMod4GB), in perl's pack "w" format (variable length base 128).

•

The unix mtime (unix seconds) in perl's pack "N" format (32 bit integer).

Optimizations¶

Limitations¶

Security issues¶

Configuration File¶

Modifying the main configuration file¶

•

Upon startup.

•

When BackupPC is sent a HUP (-1) signal. Assuming you installed the init.d script, you can also do this with "/etc/init.d/backuppc reload".

•

When the modification time of config.pl file changes. BackupPC checks the modification time once during each regular wakeup.

Configuration Parameters¶

General server configuration¶

$Conf{ServerHost} = '';

Host name on which the BackupPC server is running.

$Conf{ServerPort} = -1;

TCP port number on which the BackupPC server listens for and accepts connections. Normally this should be disabled (set to -1). The TCP port is only needed if apache runs on a different machine from BackupPC. In that case, set this to any spare port number over 1024 (eg: 2359). If you enable the TCP port, make sure you set $Conf{ServerMesgSecret} too!

$Conf{ServerMesgSecret} = '';

Shared secret to make the TCP port secure. Set this to a hard to guess string if you enable the TCP port (ie: $Conf{ServerPort} > 0).

 

To avoid possible attacks via the TCP socket interface, every client message is protected by an MD5 digest. The MD5 digest includes four items:
- a seed that is sent to the client when the connection opens
- a sequence number that increments for each message
- a shared secret that is stored in $Conf{ServerMesgSecret}
- the message itself.

 

The message is sent in plain text preceded by the MD5 digest. A snooper can see the plain-text seed sent by BackupPC and plain-text message from the client, but cannot construct a valid MD5 digest since the secret $Conf{ServerMesgSecret} is unknown. A replay attack is not possible since the seed changes on a per-connection and per-message basis.

$Conf{MyPath} = '/bin';

PATH setting for BackupPC. An explicit value is necessary for taint mode. Value shouldn't matter too much since all execs use explicit paths. However, taint mode in perl will complain if this directory is world writable.

$Conf{UmaskMode} = 027;

Permission mask for directories and files created by BackupPC. Default value prevents any access from group other, and prevents group write.

$Conf{WakeupSchedule} = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23];

Times at which we wake up, check all the PCs, and schedule necessary backups. Times are measured in hours since midnight. Can be fractional if necessary (eg: 4.25 means 4:15am).

 

If the hosts you are backing up are always connected to the network you might have only one or two wakeups each night. This will keep the backup activity after hours. On the other hand, if you are backing up laptops that are only intermittently connected to the network you will want to have frequent wakeups (eg: hourly) to maximize the chance that each laptop is backed up.

 

Examples:

 

    $Conf{WakeupSchedule} = [22.5];         # once per day at 10:30 pm.
    $Conf{WakeupSchedule} = [2,4,6,8,10,12,14,16,18,20,22];  # every 2 hours
    

 

The default value is every hour except midnight.

 

The first entry of $Conf{WakeupSchedule} is when BackupPC_nightly is run. You might want to re-arrange the entries in $Conf{WakeupSchedule} (they don't have to be ascending) so that the first entry is when you want BackupPC_nightly to run (eg: when you don't expect a lot of regular backups to run).

$Conf{MaxBackups} = 4;

Maximum number of simultaneous backups to run. If there are no user backup requests then this is the maximum number of simultaneous backups.

$Conf{MaxUserBackups} = 4;

Additional number of simultaneous backups that users can run. As many as $Conf{MaxBackups} + $Conf{MaxUserBackups} requests can run at the same time.

$Conf{MaxPendingCmds} = 15;

Maximum number of pending link commands. New backups will only be started if there are no more than $Conf{MaxPendingCmds} plus $Conf{MaxBackups} number of pending link commands, plus running jobs. This limit is to make sure BackupPC doesn't fall too far behind in running BackupPC_link commands.

$Conf{CmdQueueNice} = 10;

Nice level at which CmdQueue commands (eg: BackupPC_link and BackupPC_nightly) are run at.

$Conf{MaxBackupPCNightlyJobs} = 2;

How many BackupPC_nightly processes to run in parallel.

 

Each night, at the first wakeup listed in $Conf{WakeupSchedule}, BackupPC_nightly is run. Its job is to remove unneeded files in the pool, ie: files that only have one link. To avoid race conditions, BackupPC_nightly and BackupPC_link cannot run at the same time. Starting in v3.0.0, BackupPC_nightly can run concurrently with backups (BackupPC_dump).

 

So to reduce the elapsed time, you might want to increase this setting to run several BackupPC_nightly processes in parallel (eg: 4, or even 8).

$Conf{BackupPCNightlyPeriod} = 1;

How many days (runs) it takes BackupPC_nightly to traverse the entire pool. Normally this is 1, which means every night it runs, it does traverse the entire pool removing unused pool files.

 

Other valid values are 2, 4, 8, 16. This causes BackupPC_nightly to traverse 1/2, 1/4, 1/8 or 1/16th of the pool each night, meaning it takes 2, 4, 8 or 16 days to completely traverse the pool. The advantage is that each night the running time of BackupPC_nightly is reduced roughly in proportion, since the total job is split over multiple days. The disadvantage is that unused pool files take longer to get deleted, which will slightly increase disk usage.

 

Note that even when $Conf{BackupPCNightlyPeriod} > 1, BackupPC_nightly still runs every night. It just does less work each time it runs.

 

Examples:

 

   $Conf{BackupPCNightlyPeriod} = 1;   # entire pool is checked every night
   $Conf{BackupPCNightlyPeriod} = 2;   # two days to complete pool check
                                       # (different half each night)
   $Conf{BackupPCNightlyPeriod} = 4;   # four days to complete pool check
                                       # (different quarter each night)
    

$Conf{MaxOldLogFiles} = 14;

Maximum number of log files we keep around in log directory. These files are aged nightly. A setting of 14 means the log directory will contain about 2 weeks of old log files, in particular at most the files LOG, LOG.0, LOG.1, ... LOG.13 (except today's LOG, these files will have a .z extension if compression is on).

 

If you decrease this number after BackupPC has been running for a while you will have to manually remove the older log files.

$Conf{DfPath} = '';

Full path to the df command. Security caution: normal users should not allowed to write to this file or directory.

$Conf{DfCmd} = '$dfPath $topDir';

Command to run df. The following variables are substituted at run-time:

 

  $dfPath      path to df ($Conf{DfPath})
  $topDir      top-level BackupPC data directory
    

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{SplitPath} = '';

$Conf{ParPath} = '';

$Conf{CatPath} = '';

$Conf{GzipPath} = '';

$Conf{Bzip2Path} = '';

Full path to various commands for archiving

$Conf{DfMaxUsagePct} = 95;

Maximum threshold for disk utilization on the __TOPDIR__ filesystem. If the output from $Conf{DfPath} reports a percentage larger than this number then no new regularly scheduled backups will be run. However, user requested backups (which are usually incremental and tend to be small) are still performed, independent of disk usage. Also, currently running backups will not be terminated when the disk usage exceeds this number.

$Conf{TrashCleanSleepSec} = 300;

How long BackupPC_trashClean sleeps in seconds between each check of the trash directory. Once every 5 minutes should be reasonable.

$Conf{DHCPAddressRanges} = [];

List of DHCP address ranges we search looking for PCs to backup. This is an array of hashes for each class C address range. This is only needed if hosts in the conf/hosts file have the dhcp flag set.

 

Examples:

 

   # to specify 192.10.10.20 to 192.10.10.250 as the DHCP address pool
   $Conf{DHCPAddressRanges} = [
       {
           ipAddrBase => '192.10.10',
           first => 20,
           last  => 250,
       },
   ];
   # to specify two pools (192.10.10.20-250 and 192.10.11.10-50)
   $Conf{DHCPAddressRanges} = [
       {
           ipAddrBase => '192.10.10',
           first => 20,
           last  => 250,
       },
       {
           ipAddrBase => '192.10.11',
           first => 10,
           last  => 50,
       },
   ];
    

$Conf{BackupPCUser} = '';

The BackupPC user.

$Conf{TopDir} = '';

$Conf{ConfDir} = '';

$Conf{LogDir} = '';

$Conf{InstallDir} = '';

$Conf{CgiDir} = '';

Important installation directories:

 

  TopDir     - where all the backup data is stored
  ConfDir    - where the main config and hosts files resides
  LogDir     - where log files and other transient information
  InstallDir - where the bin, lib and doc installation dirs reside.
               Note: you cannot change this value since all the
               perl scripts include this path.  You must reinstall
               with configure.pl to change InstallDir.
  CgiDir     - Apache CGI directory for BackupPC_Admin
    

 

Note: it is STRONGLY recommended that you don't change the values here. These are set at installation time and are here for reference and are used during upgrades.

 

Instead of changing TopDir here it is recommended that you use a symbolic link to the new location, or mount the new BackupPC store at the existing $Conf{TopDir} setting.

$Conf{BackupPCUserVerify} = 1;

Whether BackupPC and the CGI script BackupPC_Admin verify that they are really running as user $Conf{BackupPCUser}. If this flag is set and the effective user id (euid) differs from $Conf{BackupPCUser} then both scripts exit with an error. This catches cases where BackupPC might be accidently started as root or the wrong user, or if the CGI script is not installed correctly.

$Conf{HardLinkMax} = 31999;

Maximum number of hardlinks supported by the $TopDir file system that BackupPC uses. Most linux or unix file systems should support at least 32000 hardlinks per file, or 64000 in other cases. If a pool file already has this number of hardlinks, a new pool file is created so that new hardlinks can be accommodated. This limit will only be hit if an identical file appears at least this number of times across all the backups.

$Conf{PerlModuleLoad} = undef;

Advanced option for asking BackupPC to load additional perl modules. Can be a list (array ref) of module names to load at startup.

$Conf{ServerInitdPath} = '';

$Conf{ServerInitdStartCmd} = '';

Path to init.d script and command to use that script to start the server from the CGI interface. The following variables are substituted at run-time:

 

  $sshPath           path to ssh ($Conf{SshPath})
  $serverHost        same as $Conf{ServerHost}
  $serverInitdPath   path to init.d script ($Conf{ServerInitdPath})
    

 

Example:

 

$Conf{ServerInitdPath} = '/etc/init.d/backuppc'; $Conf{ServerInitdStartCmd} = '$sshPath -q -x -l root $serverHost'
. ' $serverInitdPath start'
. ' < /dev/null >& /dev/null';

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

What to backup and when to do it¶

$Conf{FullPeriod} = 6.97;

Minimum period in days between full backups. A full dump will only be done if at least this much time has elapsed since the last full dump, and at least $Conf{IncrPeriod} days has elapsed since the last successful dump.

 

Typically this is set slightly less than an integer number of days. The time taken for the backup, plus the granularity of $Conf{WakeupSchedule} will make the actual backup interval a bit longer.

$Conf{IncrPeriod} = 0.97;

Minimum period in days between incremental backups (a user requested incremental backup will be done anytime on demand).

 

Typically this is set slightly less than an integer number of days. The time taken for the backup, plus the granularity of $Conf{WakeupSchedule} will make the actual backup interval a bit longer.

$Conf{FullKeepCnt} = 1;

Number of full backups to keep. Must be >= 1.

 

In the steady state, each time a full backup completes successfully the oldest one is removed. If this number is decreased, the extra old backups will be removed.

 

If filling of incremental dumps is off the oldest backup always has to be a full (ie: filled) dump. This might mean one or two extra full dumps are kept until the oldest incremental backups expire.

 

Exponential backup expiry is also supported. This allows you to specify:

 

  - num fulls to keep at intervals of 1 * $Conf{FullPeriod}, followed by
  - num fulls to keep at intervals of 2 * $Conf{FullPeriod},
  - num fulls to keep at intervals of 4 * $Conf{FullPeriod},
  - num fulls to keep at intervals of 8 * $Conf{FullPeriod},
  - num fulls to keep at intervals of 16 * $Conf{FullPeriod},
    

 

and so on. This works by deleting every other full as each expiry boundary is crossed.

 

Exponential expiry is specified using an array for $Conf{FullKeepCnt}:

 

  $Conf{FullKeepCnt} = [4, 2, 3];
    

 

Entry #n specifies how many fulls to keep at an interval of 2^n * $Conf{FullPeriod} (ie: 1, 2, 4, 8, 16, 32, ...).

 

The example above specifies keeping 4 of the most recent full backups (1 week interval) two full backups at 2 week intervals, and 3 full backups at 4 week intervals, eg:

 

   full 0 19 weeks old   \
   full 1 15 weeks old    >---  3 backups at 4 * $Conf{FullPeriod}
   full 2 11 weeks old   /
   full 3  7 weeks old   \____  2 backups at 2 * $Conf{FullPeriod}
   full 4  5 weeks old   /
   full 5  3 weeks old   \
   full 6  2 weeks old    \___  4 backups at 1 * $Conf{FullPeriod}
   full 7  1 week old     /
   full 8  current       /
    

 

On a given week the spacing might be less than shown as each backup ages through each expiry period. For example, one week later, a new full is completed and the oldest is deleted, giving:

 

   full 0 16 weeks old   \
   full 1 12 weeks old    >---  3 backups at 4 * $Conf{FullPeriod}
   full 2  8 weeks old   /
   full 3  6 weeks old   \____  2 backups at 2 * $Conf{FullPeriod}
   full 4  4 weeks old   /
   full 5  3 weeks old   \
   full 6  2 weeks old    \___  4 backups at 1 * $Conf{FullPeriod}
   full 7  1 week old     /
   full 8  current       /
    

 

You can specify 0 as a count (except in the first entry), and the array can be as long as you wish. For example:

 

  $Conf{FullKeepCnt} = [4, 0, 4, 0, 0, 2];
    

 

This will keep 10 full dumps, 4 most recent at 1 * $Conf{FullPeriod}, followed by 4 at an interval of 4 * $Conf{FullPeriod} (approx 1 month apart), and then 2 at an interval of 32 * $Conf{FullPeriod} (approx 7-8 months apart).

 

Example: these two settings are equivalent and both keep just the four most recent full dumps:

 

   $Conf{FullKeepCnt} = 4;
   $Conf{FullKeepCnt} = [4];
    

$Conf{FullKeepCntMin} = 1;

$Conf{FullAgeMax} = 90;

Very old full backups are removed after $Conf{FullAgeMax} days. However, we keep at least $Conf{FullKeepCntMin} full backups no matter how old they are.

 

Note that $Conf{FullAgeMax} will be increased to $Conf{FullKeepCnt} times $Conf{FullPeriod} if $Conf{FullKeepCnt} specifies enough full backups to exceed $Conf{FullAgeMax}.

$Conf{IncrKeepCnt} = 6;

Number of incremental backups to keep. Must be >= 1.

 

In the steady state, each time an incr backup completes successfully the oldest one is removed. If this number is decreased, the extra old backups will be removed.

$Conf{IncrKeepCntMin} = 1;

$Conf{IncrAgeMax} = 30;

Very old incremental backups are removed after $Conf{IncrAgeMax} days. However, we keep at least $Conf{IncrKeepCntMin} incremental backups no matter how old they are.

$Conf{IncrLevels} = [1];

Level of each incremental. "Level" follows the terminology of dump(1). A full backup has level 0. A new incremental of level N will backup all files that have changed since the most recent backup of a lower level.

 

The entries of $Conf{IncrLevels} apply in order to each incremental after each full backup. It wraps around until the next full backup. For example, these two settings have the same effect:

 

      $Conf{IncrLevels} = [1, 2, 3];
      $Conf{IncrLevels} = [1, 2, 3, 1, 2, 3];
    

 

This means the 1st and 4th incrementals (level 1) go all the way back to the full. The 2nd and 3rd (and 5th and 6th) backups just go back to the immediate preceeding incremental.

 

Specifying a sequence of multi-level incrementals will usually mean more than $Conf{IncrKeepCnt} incrementals will need to be kept, since lower level incrementals are needed to merge a complete view of a backup. For example, with

 

      $Conf{FullPeriod}  = 7;
      $Conf{IncrPeriod}  = 1;
      $Conf{IncrKeepCnt} = 6;
      $Conf{IncrLevels}  = [1, 2, 3, 4, 5, 6];
    

 

there will be up to 11 incrementals in this case:

 

      backup #0  (full, level 0, oldest)
      backup #1  (incr, level 1)
      backup #2  (incr, level 2)
      backup #3  (incr, level 3)
      backup #4  (incr, level 4)
      backup #5  (incr, level 5)
      backup #6  (incr, level 6)
      backup #7  (full, level 0)
      backup #8  (incr, level 1)
      backup #9  (incr, level 2)
      backup #10 (incr, level 3)
      backup #11 (incr, level 4)
      backup #12 (incr, level 5, newest)
    

 

Backup #1 (the oldest level 1 incremental) can't be deleted since backups 2..6 depend on it. Those 6 incrementals can't all be deleted since that would only leave 5 (#8..12). When the next incremental happens (level 6), the complete set of 6 older incrementals (#1..6) will be deleted, since that maintains the required number ($Conf{IncrKeepCnt}) of incrementals. This situation is reduced if you set shorter chains of multi-level incrementals, eg:

 

      $Conf{IncrLevels}  = [1, 2, 3];
    

 

would only have up to 2 extra incremenals before all 3 are deleted.

 

BackupPC as usual merges the full and the sequence of incrementals together so each incremental can be browsed and restored as though it is a complete backup. If you specify a long chain of incrementals then more backups need to be merged when browsing, restoring, or getting the starting point for rsync backups. In the example above (levels 1..6), browing backup #6 requires 7 different backups (#0..6) to be merged.

 

Because of this merging and the additional incrementals that need to be kept, it is recommended that some level 1 incrementals be included in $Conf{IncrLevels}.

 

Prior to version 3.0 incrementals were always level 1, meaning each incremental backed up all the files that changed since the last full.

$Conf{BackupsDisable} = 0;

Disable all full and incremental backups. These settings are useful for a client that is no longer being backed up (eg: a retired machine), but you wish to keep the last backups available for browsing or restoring to other machines.

 

There are three values for $Conf{BackupsDisable}:

 

  0    Backups are enabled.
  1    Don't do any regular backups on this client.  Manually
       requested backups (via the CGI interface) will still occur.
  2    Don't do any backups on this client.  Manually requested
       backups (via the CGI interface) will be ignored.
    

 

In versions prior to 3.0 Backups were disabled by setting $Conf{FullPeriod} to -1 or -2.

$Conf{PartialAgeMax} = 3;

A failed full backup is saved as a partial backup. The rsync XferMethod can take advantage of the partial full when the next backup is run. This parameter sets the age of the partial full in days: if the partial backup is older than this number of days, then rsync will ignore (not use) the partial full when the next backup is run. If you set this to a negative value then no partials will be saved. If you set this to 0, partials will be saved, but will not be used by the next backup.

 

The default setting of 3 days means that a partial older than 3 days is ignored when the next full backup is done.

$Conf{IncrFill} = 0;

Whether incremental backups are filled. "Filling" means that the most recent full (or filled) dump is merged into the new incremental dump using hardlinks. This makes an incremental dump look like a full dump. Prior to v1.03 all incremental backups were filled. In v1.4.0 and later the default is off.

 

BackupPC, and the cgi interface in particular, do the right thing on un-filled incremental backups. It will correctly display the merged incremental backup with the most recent filled backup, giving the un-filled incremental backups a filled appearance. That means it invisible to the user whether incremental dumps are filled or not.

 

Filling backups takes a little extra disk space, and it does cost some extra disk activity for filling, and later removal. Filling is no longer useful, since file mangling and compression doesn't make a filled backup very useful. It's likely the filling option will be removed from future versions: filling will be delegated to the display and extraction of backup data.

 

If filling is off, BackupPC makes sure that the oldest backup is a full, otherwise the following incremental backups will be incomplete. This might mean an extra full backup has to be kept until the following incremental backups expire.

 

The default is off. You can turn this on or off at any time without affecting existing backups.

$Conf{RestoreInfoKeepCnt} = 10;

Number of restore logs to keep. BackupPC remembers information about each restore request. This number per client will be kept around before the oldest ones are pruned.

 

Note: files/dirs delivered via Zip or Tar downloads don't count as restores. Only the first restore option (where the files and dirs are written to the host) count as restores that are logged.

$Conf{ArchiveInfoKeepCnt} = 10;

Number of archive logs to keep. BackupPC remembers information about each archive request. This number per archive client will be kept around before the oldest ones are pruned.

$Conf{BackupFilesOnly} = undef;

List of directories or files to backup. If this is defined, only these directories or files will be backed up.

 

For Smb, only one of $Conf{BackupFilesExclude} and $Conf{BackupFilesOnly} can be specified per share. If both are set for a particular share, then $Conf{BackupFilesOnly} takes precedence and $Conf{BackupFilesExclude} is ignored.

 

This can be set to a string, an array of strings, or, in the case of multiple shares, a hash of strings or arrays. A hash is used to give a list of directories or files to backup for each share (the share name is the key). If this is set to just a string or array, and $Conf{SmbShareName} contains multiple share names, then the setting is assumed to apply all shares.

 

If a hash is used, a special key "*" means it applies to all shares that don't have a specific entry.

 

Examples:

 

   $Conf{BackupFilesOnly} = '/myFiles';
   $Conf{BackupFilesOnly} = ['/myFiles'];     # same as first example
   $Conf{BackupFilesOnly} = ['/myFiles', '/important'];
   $Conf{BackupFilesOnly} = {
      'c' => ['/myFiles', '/important'],      # these are for 'c' share
      'd' => ['/moreFiles', '/archive'],      # these are for 'd' share
   };
   $Conf{BackupFilesOnly} = {
      'c' => ['/myFiles', '/important'],      # these are for 'c' share
      '*' => ['/myFiles', '/important'],      # these are other shares
   };
    

$Conf{BackupFilesExclude} = undef;

List of directories or files to exclude from the backup. For Smb, only one of $Conf{BackupFilesExclude} and $Conf{BackupFilesOnly} can be specified per share. If both are set for a particular share, then $Conf{BackupFilesOnly} takes precedence and $Conf{BackupFilesExclude} is ignored.

 

This can be set to a string, an array of strings, or, in the case of multiple shares, a hash of strings or arrays. A hash is used to give a list of directories or files to exclude for each share (the share name is the key). If this is set to just a string or array, and $Conf{SmbShareName} contains multiple share names, then the setting is assumed to apply to all shares.

 

The exact behavior is determined by the underlying transport program, smbclient or tar. For smbclient the exlclude file list is passed into the X option. Simple shell wild-cards using "*" or "?" are allowed.

 

For tar, if the exclude file contains a "/" it is assumed to be anchored at the start of the string. Since all the tar paths start with "./", BackupPC prepends a "." if the exclude file starts with a "/". Note that GNU tar version >= 1.13.7 is required for the exclude option to work correctly. For linux or unix machines you should add "/proc" to $Conf{BackupFilesExclude} unless you have specified --one-file-system in $Conf{TarClientCmd} or --one-file-system in $Conf{RsyncArgs}. Also, for tar, do not use a trailing "/" in the directory name: a trailing "/" causes the name to not match and the directory will not be excluded.

 

Users report that for smbclient you should specify a directory followed by "/*", eg: "/proc/*", instead of just "/proc".

 

FTP servers are traversed recursively so excluding directories will also exclude its contents. You can use the wildcard characters "*" and "?" to define files for inclusion and exclusion. Both attributes $Conf{BackupFilesOnly} and $Conf{BackupFilesExclude} can be defined for the same share.

 

If a hash is used, a special key "*" means it applies to all shares that don't have a specific entry.

 

Examples:

 

   $Conf{BackupFilesExclude} = '/temp';
   $Conf{BackupFilesExclude} = ['/temp'];     # same as first example
   $Conf{BackupFilesExclude} = ['/temp', '/winnt/tmp'];
   $Conf{BackupFilesExclude} = {
      'c' => ['/temp', '/winnt/tmp'],         # these are for 'c' share
      'd' => ['/junk', '/dont_back_this_up'], # these are for 'd' share
   };
   $Conf{BackupFilesExclude} = {
      'c' => ['/temp', '/winnt/tmp'],         # these are for 'c' share
      '*' => ['/junk', '/dont_back_this_up'], # these are for other shares
   };
    

$Conf{BlackoutBadPingLimit} = 3;

$Conf{BlackoutGoodCnt} = 7;

PCs that are always or often on the network can be backed up after hours, to reduce PC, network and server load during working hours. For each PC a count of consecutive good pings is maintained. Once a PC has at least $Conf{BlackoutGoodCnt} consecutive good pings it is subject to "blackout" and not backed up during hours and days specified by $Conf{BlackoutPeriods}.

 

To allow for periodic rebooting of a PC or other brief periods when a PC is not on the network, a number of consecutive bad pings is allowed before the good ping count is reset. This parameter is $Conf{BlackoutBadPingLimit}.

 

Note that bad and good pings don't occur with the same interval. If a machine is always on the network, it will only be pinged roughly once every $Conf{IncrPeriod} (eg: once per day). So a setting for $Conf{BlackoutGoodCnt} of 7 means it will take around 7 days for a machine to be subject to blackout. On the other hand, if a ping is failed, it will be retried roughly every time BackupPC wakes up, eg, every one or two hours. So a setting for $Conf{BlackoutBadPingLimit} of 3 means that the PC will lose its blackout status after 3-6 hours of unavailability.

 

To disable the blackout feature set $Conf{BlackoutGoodCnt} to a negative value. A value of 0 will make all machines subject to blackout. But if you don't want to do any backups during the day it would be easier to just set $Conf{WakeupSchedule} to a restricted schedule.

$Conf{BlackoutPeriods} = [ ... ];

One or more blackout periods can be specified. If a client is subject to blackout then no regular (non-manual) backups will be started during any of these periods. hourBegin and hourEnd specify hours fro midnight and weekDays is a list of days of the week where 0 is Sunday, 1 is Monday etc.

 

For example:

 

   $Conf{BlackoutPeriods} = [
        {
            hourBegin =>  7.0,
            hourEnd   => 19.5,
            weekDays  => [1, 2, 3, 4, 5],
        },
   ];
    

 

specifies one blackout period from 7:00am to 7:30pm local time on Mon-Fri.

 

The blackout period can also span midnight by setting hourBegin > hourEnd, eg:

 

   $Conf{BlackoutPeriods} = [
        {
            hourBegin =>  7.0,
            hourEnd   => 19.5,
            weekDays  => [1, 2, 3, 4, 5],
        },
        {
            hourBegin => 23,
            hourEnd   =>  5,
            weekDays  => [5, 6],
        },
   ];
    

 

This specifies one blackout period from 7:00am to 7:30pm local time on Mon-Fri, and a second period from 11pm to 5am on Friday and Saturday night.

$Conf{BackupZeroFilesIsFatal} = 1;

A backup of a share that has zero files is considered fatal. This is used to catch miscellaneous Xfer errors that result in no files being backed up. If you have shares that might be empty (and therefore an empty backup is valid) you should set this flag to 0.

How to backup a client¶

$Conf{XferMethod} = 'smb';

What transport method to use to backup each host. If you have a mixed set of WinXX and linux/unix hosts you will need to override this in the per-PC config.pl.

 

The valid values are:

 

  - 'smb':     backup and restore via smbclient and the SMB protocol.
               Easiest choice for WinXX.
  - 'rsync':   backup and restore via rsync (via rsh or ssh).
               Best choice for linux/unix.  Good choice also for WinXX.
  - 'rsyncd':  backup and restore via rsync daemon on the client.
               Best choice for linux/unix if you have rsyncd running on
               the client.  Good choice also for WinXX.
  - 'tar':    backup and restore via tar, tar over ssh, rsh or nfs.
              Good choice for linux/unix.
  - 'archive': host is a special archive host.  Backups are not done.
               An archive host is used to archive other host's backups
               to permanent media, such as tape, CDR or DVD.
    

$Conf{XferLogLevel} = 1;

Level of verbosity in Xfer log files. 0 means be quiet, 1 will give will give one line per file, 2 will also show skipped files on incrementals, higher values give more output.

$Conf{ClientCharset} = '';

Filename charset encoding on the client. BackupPC uses utf8 on the server for filename encoding. If this is empty, then utf8 is assumed and client filenames will not be modified. If set to a different encoding then filenames will converted to/from utf8 automatically during backup and restore.

 

If the file names displayed in the browser (eg: accents or special characters) don't look right then it is likely you haven't set $Conf{ClientCharset} correctly.

 

If you are using smbclient on a WinXX machine, smbclient will convert to the "unix charset" setting in smb.conf. The default is utf8, in which case leave $Conf{ClientCharset} empty since smbclient does the right conversion.

 

If you are using rsync on a WinXX machine then it does no conversion. A typical WinXX encoding for latin1/western europe is 'cp1252', so in this case set $Conf{ClientCharset} to 'cp1252'.

 

On a linux or unix client, run "locale charmap" to see the client's charset. Set $Conf{ClientCharset} to this value. A typical value for english/US is 'ISO-8859-1'.

 

Do "perldoc Encode::Supported" to see the list of possible charset values. The FAQ at http://www.cl.cam.ac.uk/~mgk25/unicode.html is excellent, and http://czyborra.com/charsets/iso8859.html provides more information on the iso-8859 charsets.

$Conf{ClientCharsetLegacy} = 'iso-8859-1';

Prior to 3.x no charset conversion was done by BackupPC. Backups were stored in what ever charset the XferMethod provided - typically utf8 for smbclient and the client's locale settings for rsync and tar (eg: cp1252 for rsync on WinXX and perhaps iso-8859-1 with rsync on linux). This setting tells BackupPC the charset that was used to store file names in old backups taken with BackupPC 2.x, so that non-ascii file names in old backups can be viewed and restored.

Samba Configuration¶

$Conf{SmbShareName} = 'C$';

Name of the host share that is backed up when using SMB. This can be a string or an array of strings if there are multiple shares per host. Examples:

 

  $Conf{SmbShareName} = 'c';          # backup 'c' share
  $Conf{SmbShareName} = ['c', 'd'];   # backup 'c' and 'd' shares
    

 

This setting only matters if $Conf{XferMethod} = 'smb'.

$Conf{SmbShareUserName} = '';

Smbclient share user name. This is passed to smbclient's -U argument.

 

This setting only matters if $Conf{XferMethod} = 'smb'.

$Conf{SmbSharePasswd} = '';

Smbclient share password. This is passed to smbclient via its PASSWD environment variable. There are several ways you can tell BackupPC the smb share password. In each case you should be very careful about security. If you put the password here, make sure that this file is not readable by regular users! See the "Setting up config.pl" section in the documentation for more information.

 

This setting only matters if $Conf{XferMethod} = 'smb'.

$Conf{SmbClientPath} = '';

Full path for smbclient. Security caution: normal users should not allowed to write to this file or directory.

 

smbclient is from the Samba distribution. smbclient is used to actually extract the incremental or full dump of the share filesystem from the PC.

 

This setting only matters if $Conf{XferMethod} = 'smb'.

$Conf{SmbClientFullCmd} = '$smbClientPath \\\\$host\\$shareName' ...

Command to run smbclient for a full dump. This setting only matters if $Conf{XferMethod} = 'smb'.

 

The following variables are substituted at run-time:

 

   $smbClientPath   same as $Conf{SmbClientPath}
   $host            host to backup/restore
   $hostIP          host IP address
   $shareName       share name
   $userName        user name
   $fileList        list of files to backup (based on exclude/include)
   $I_option        optional -I option to smbclient
   $X_option        exclude option (if $fileList is an exclude list)
   $timeStampFile   start time for incremental dump
    

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{SmbClientIncrCmd} = '$smbClientPath \\\\$host\\$shareName' ...

Command to run smbclient for an incremental dump. This setting only matters if $Conf{XferMethod} = 'smb'.

 

Same variable substitutions are applied as $Conf{SmbClientFullCmd}.

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{SmbClientRestoreCmd} = '$smbClientPath \\\\$host\\$shareName' ...

Command to run smbclient for a restore. This setting only matters if $Conf{XferMethod} = 'smb'.

 

Same variable substitutions are applied as $Conf{SmbClientFullCmd}.

 

If your smb share is read-only then direct restores will fail. You should set $Conf{SmbClientRestoreCmd} to undef and the corresponding CGI restore option will be removed.

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

Tar Configuration¶

$Conf{TarShareName} = '/';

Which host directories to backup when using tar transport. This can be a string or an array of strings if there are multiple directories to backup per host. Examples:

 

  $Conf{TarShareName} = '/';                    # backup everything
  $Conf{TarShareName} = '/home';                # only backup /home
  $Conf{TarShareName} = ['/home', '/src'];      # backup /home and /src
    

 

The fact this parameter is called 'TarShareName' is for historical consistency with the Smb transport options. You can use any valid directory on the client: there is no need for it to correspond to any Smb share or device mount point.

 

Note also that you can also use $Conf{BackupFilesOnly} to specify a specific list of directories to backup. It's more efficient to use this option instead of $Conf{TarShareName} since a new tar is run for each entry in $Conf{TarShareName}.

 

On the other hand, if you add --one-file-system to $Conf{TarClientCmd} you can backup each file system separately, which makes restoring one bad file system easier. In this case you would list all of the mount points here, since you can't get the same result with $Conf{BackupFilesOnly}:

 

    $Conf{TarShareName} = ['/', '/var', '/data', '/boot'];
    

 

This setting only matters if $Conf{XferMethod} = 'tar'.

$Conf{TarClientCmd} = '$sshPath -q -x -n -l root $host' ...

Full command to run tar on the client. GNU tar is required. You will need to fill in the correct paths for ssh2 on the local host (server) and GNU tar on the client. Security caution: normal users should not allowed to write to these executable files or directories.

 

See the documentation for more information about setting up ssh2 keys.

 

If you plan to use NFS then tar just runs locally and ssh2 is not needed. For example, assuming the client filesystem is mounted below /mnt/hostName, you could use something like:

 

   $Conf{TarClientCmd} = '$tarPath -c -v -f - -C /mnt/$host/$shareName'
                       . ' --totals';
    

 

In the case of NFS or rsh you need to make sure BackupPC's privileges are sufficient to read all the files you want to backup. Also, you will probably want to add "/proc" to $Conf{BackupFilesExclude}.

 

The following variables are substituted at run-time:

 

  $host        host name
  $hostIP      host's IP address
  $incrDate    newer-than date for incremental backups
  $shareName   share name to backup (ie: top-level directory path)
  $fileList    specific files to backup or exclude
  $tarPath     same as $Conf{TarClientPath}
  $sshPath     same as $Conf{SshPath}
    

 

If a variable is followed by a "+" it is shell escaped. This is necessary for the command part of ssh or rsh, since it ends up getting passed through the shell.

 

This setting only matters if $Conf{XferMethod} = 'tar'.

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{TarFullArgs} = '$fileList+';

Extra tar arguments for full backups. Several variables are substituted at run-time. See $Conf{TarClientCmd} for the list of variable substitutions.

 

If you are running tar locally (ie: without rsh or ssh) then remove the "+" so that the argument is no longer shell escaped.

 

This setting only matters if $Conf{XferMethod} = 'tar'.

$Conf{TarIncrArgs} = '--newer=$incrDate+ $fileList+';

Extra tar arguments for incr backups. Several variables are substituted at run-time. See $Conf{TarClientCmd} for the list of variable substitutions.

 

Note that GNU tar has several methods for specifying incremental backups, including:

 

  --newer-mtime $incrDate+
         This causes a file to be included if the modification time is
         later than $incrDate (meaning its contents might have changed).
         But changes in the ownership or modes will not qualify the
         file to be included in an incremental.
  --newer=$incrDate+
         This causes the file to be included if any attribute of the
         file is later than $incrDate, meaning either attributes or
         the modification time.  This is the default method.  Do
         not use --atime-preserve in $Conf{TarClientCmd} above,
         otherwise resetting the atime (access time) counts as an
         attribute change, meaning the file will always be included
         in each new incremental dump.
    

 

If you are running tar locally (ie: without rsh or ssh) then remove the "+" so that the argument is no longer shell escaped.

 

This setting only matters if $Conf{XferMethod} = 'tar'.

$Conf{TarClientRestoreCmd} = '$sshPath -q -x -l root $host' ...

Full command to run tar for restore on the client. GNU tar is required. This can be the same as $Conf{TarClientCmd}, with tar's -c replaced by -x and ssh's -n removed.

 

See $Conf{TarClientCmd} for full details.

 

This setting only matters if $Conf{XferMethod} = "tar".

 

If you want to disable direct restores using tar, you should set $Conf{TarClientRestoreCmd} to undef and the corresponding CGI restore option will be removed.

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{TarClientPath} = '';

Full path for tar on the client. Security caution: normal users should not allowed to write to this file or directory.

 

This setting only matters if $Conf{XferMethod} = 'tar'.

Rsync/Rsyncd Configuration¶

$Conf{RsyncClientPath} = '';

Path to rsync executable on the client

$Conf{RsyncClientCmd} = '$sshPath -q -x -l root $host $rsyncPath $argList+';

Full command to run rsync on the client machine. The following variables are substituted at run-time:

 

       $host           host name being backed up
       $hostIP         host's IP address
       $shareName      share name to backup (ie: top-level directory path)
       $rsyncPath      same as $Conf{RsyncClientPath}
       $sshPath        same as $Conf{SshPath}
       $argList        argument list, built from $Conf{RsyncArgs},
                       $shareName, $Conf{BackupFilesExclude} and
                       $Conf{BackupFilesOnly}
    

 

This setting only matters if $Conf{XferMethod} = 'rsync'.

$Conf{RsyncClientRestoreCmd} = '$sshPath -q -x -l root $host $rsyncPath $argList+';

Full command to run rsync for restore on the client. The following variables are substituted at run-time:

 

       $host           host name being backed up
       $hostIP         host's IP address
       $shareName      share name to backup (ie: top-level directory path)
       $rsyncPath      same as $Conf{RsyncClientPath}
       $sshPath        same as $Conf{SshPath}
       $argList        argument list, built from $Conf{RsyncArgs},
                       $shareName, $Conf{BackupFilesExclude} and
                       $Conf{BackupFilesOnly}
    

 

This setting only matters if $Conf{XferMethod} = 'rsync'.

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{RsyncShareName} = '/';

Share name to backup. For $Conf{XferMethod} = "rsync" this should be a file system path, eg '/' or '/home'.

 

For $Conf{XferMethod} = "rsyncd" this should be the name of the module to backup (ie: the name from /etc/rsynd.conf).

 

This can also be a list of multiple file system paths or modules. For example, by adding --one-file-system to $Conf{RsyncArgs} you can backup each file system separately, which makes restoring one bad file system easier. In this case you would list all of the mount points:

 

    $Conf{RsyncShareName} = ['/', '/var', '/data', '/boot'];
    

$Conf{RsyncdClientPort} = 873;

Rsync daemon port on the client, for $Conf{XferMethod} = "rsyncd".

$Conf{RsyncdUserName} = '';

Rsync daemon user name on client, for $Conf{XferMethod} = "rsyncd". The user name and password are stored on the client in whatever file the "secrets file" parameter in rsyncd.conf points to (eg: /etc/rsyncd.secrets).

$Conf{RsyncdPasswd} = '';

Rsync daemon user name on client, for $Conf{XferMethod} = "rsyncd". The user name and password are stored on the client in whatever file the "secrets file" parameter in rsyncd.conf points to (eg: /etc/rsyncd.secrets).

$Conf{RsyncdAuthRequired} = 1;

Whether authentication is mandatory when connecting to the client's rsyncd. By default this is on, ensuring that BackupPC will refuse to connect to an rsyncd on the client that is not password protected. Turn off at your own risk.

$Conf{RsyncCsumCacheVerifyProb} = 0.01;

When rsync checksum caching is enabled (by adding the --checksum-seed=32761 option to $Conf{RsyncArgs}), the cached checksums can be occasionally verified to make sure the file contents matches the cached checksums. This is to avoid the risk that disk problems might cause the pool file contents to get corrupted, but the cached checksums would make BackupPC think that the file still matches the client.

 

This setting is the probability (0 means never and 1 means always) that a file will be rechecked. Setting it to 0 means the checksums will not be rechecked (unless there is a phase 0 failure). Setting it to 1 (ie: 100%) means all files will be checked, but that is not a desirable setting since you are better off simply turning caching off (ie: remove the --checksum-seed option).

 

The default of 0.01 means 1% (on average) of the files during a full backup will have their cached checksum re-checked.

 

This setting has no effect unless checksum caching is turned on.

$Conf{RsyncArgs} = [ ... ];

Arguments to rsync for backup. Do not edit the first set unless you have a thorough understanding of how File::RsyncP works.

$Conf{RsyncArgsExtra} = [];

Additional arguments added to RsyncArgs. This can be used in conbination with $Conf{RsyncArgs} to allow customization of the rsync arguments on a part-client basis. The standard arguments go in $Conf{RsyncArgs} and $Conf{RsyncArgsExtra} can be set on a per-client basis.

 

Examples of additional arguments that should work are --exclude/--include, eg:

 

    $Conf{RsyncArgsExtra} = [
          '--exclude', '/proc',
          '--exclude', '*.tmp',
    ];
    

 

Both $Conf{RsyncArgs} and $Conf{RsyncArgsExtra} are subject to the following variable substitutions:

 

       $client       client name being backed up
       $host         host name (could be different from client name if
                                $Conf{ClientNameAlias} is set)
       $hostIP       IP address of host
       $confDir      configuration directory path
    

 

This allows settings of the form:

 

    $Conf{RsyncArgsExtra} = [
            '--exclude-from=$confDir/pc/$host.exclude',
    ];
    

$Conf{RsyncRestoreArgs} = [ ... ];

Arguments to rsync for restore. Do not edit the first set unless you have a thorough understanding of how File::RsyncP works.

 

If you want to disable direct restores using rsync (eg: is the module is read-only), you should set $Conf{RsyncRestoreArgs} to undef and the corresponding CGI restore option will be removed.

 

$Conf{RsyncRestoreArgs} is subject to the following variable substitutions:

 

       $client       client name being backed up
       $host         host name (could be different from client name if
                                $Conf{ClientNameAlias} is set)
       $hostIP       IP address of host
       $confDir      configuration directory path
    

 

Note: $Conf{RsyncArgsExtra} doesn't apply to $Conf{RsyncRestoreArgs}.

FTP Configuration¶

$Conf{FtpShareName} = '';

Which host directories to backup when using FTP. This can be a string or an array of strings if there are multiple shares per host.

 

This value must be specified in one of two ways: either as a subdirectory of the 'share root' on the server, or as the absolute path of the directory.

 

In the following example, if the directory /home/username is the root share of the ftp server with the given username, the following two values will back up the same directory:

 

   $Conf{FtpShareName} = 'www';                # www directory
   $Conf{FtpShareName} = '/home/username/www'; # same directory
    

 

Path resolution is not supported; i.e.; you may not have an ftp share path defined as '../otheruser' or '~/games'.

 

 Multiple shares may also be specified, as with other protocols:
   $Conf{FtpShareName} = [ 'www',
                           'bin',
                           'config' ];
    

 

Note also that you can also use $Conf{BackupFilesOnly} to specify a specific list of directories to backup. It's more efficient to use this option instead of $Conf{FtpShareName} since a new tar is run for each entry in $Conf{FtpShareName}.

 

This setting only matters if $Conf{XferMethod} = 'ftp'.

$Conf{FtpUserName} = '';

FTP user name. This is used to log into the server.

 

This setting is used only if $Conf{XferMethod} = 'ftp'.

$Conf{FtpPasswd} = '';

FTP user password. This is used to log into the server.

 

This setting is used only if $Conf{XferMethod} = 'ftp'.

$Conf{FtpPassive} = 1;

Whether passive mode is used. The correct setting depends upon whether local or remote ports are accessible from the other machine, which is affected by any firewall or routers between the FTP server on the client and the BackupPC server.

 

This setting is used only if $Conf{XferMethod} = 'ftp'.

$Conf{FtpBlockSize} = 10240;

Transfer block size. This sets the size of the amounts of data in each frame. While undefined, this value takes the default value.

 

This setting is used only if $Conf{XferMethod} = 'ftp'.

$Conf{FtpPort} = 21;

The port of the ftp server. If undefined, 21 is used.

 

This setting is used only if $Conf{XferMethod} = 'ftp'.

$Conf{FtpTimeout} = 120;

Connection timeout for FTP. When undefined, the default is 120 seconds.

 

This setting is used only if $Conf{XferMethod} = 'ftp'.

$Conf{FtpFollowSymlinks} = 0;

Behaviour when BackupPC encounters symlinks on the FTP share.

 

Symlinks cannot be restored via FTP, so the desired behaviour will be different depending on the setup of the share. The default for this behavor is 1. Directory shares with more complicated directory structures should consider other protocols.

Archive Configuration¶

$Conf{ArchiveDest} = '/tmp';

Archive Destination

 

The Destination of the archive e.g. /tmp for file archive or /dev/nst0 for device archive

$Conf{ArchiveComp} = 'gzip';

Archive Compression type

 

The valid values are:

 

  - 'none':  No Compression
  - 'gzip':  Medium Compression. Recommended.
  - 'bzip2': High Compression but takes longer.
    

$Conf{ArchivePar} = 0;

Archive Parity Files

 

The amount of Parity data to generate, as a percentage of the archive size. Uses the commandline par2 (par2cmdline) available from http://parchive.sourceforge.net

 

Only useful for file dumps.

 

Set to 0 to disable this feature.

$Conf{ArchiveSplit} = 0;

Archive Size Split

 

Only for file archives. Splits the output into the specified size * 1,000,000. e.g. to split into 650,000,000 bytes, specify 650 below.

 

If the value is 0, or if $Conf{ArchiveDest} is an existing file or device (e.g. a streaming tape drive), this feature is disabled.

$Conf{ArchiveClientCmd} = '$Installdir/bin/BackupPC_archiveHost' ...

Archive Command

 

This is the command that is called to actually run the archive process for each host. The following variables are substituted at run-time:

 

  $Installdir    The installation directory of BackupPC
  $tarCreatePath The path to BackupPC_tarCreate
  $splitpath     The path to the split program
  $parpath       The path to the par2 program
  $host          The host to archive
  $backupnumber  The backup number of the host to archive
  $compression   The path to the compression program
  $compext       The extension assigned to the compression type
  $splitsize     The number of bytes to split archives into
  $archiveloc    The location to put the archive
  $parfile       The amount of parity data to create (percentage)
    

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{SshPath} = '';

Full path for ssh. Security caution: normal users should not allowed to write to this file or directory.

$Conf{NmbLookupPath} = '';

Full path for nmblookup. Security caution: normal users should not allowed to write to this file or directory.

 

nmblookup is from the Samba distribution. nmblookup is used to get the netbios name, necessary for DHCP hosts.

$Conf{NmbLookupCmd} = '$nmbLookupPath -A $host';

NmbLookup command. Given an IP address, does an nmblookup on that IP address. The following variables are substituted at run-time:

 

  $nmbLookupPath      path to nmblookup ($Conf{NmbLookupPath})
  $host               IP address
    

 

This command is only used for DHCP hosts: given an IP address, this command should try to find its NetBios name.

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{NmbLookupFindHostCmd} = '$nmbLookupPath $host';

NmbLookup command. Given a netbios name, finds that host by doing a NetBios lookup. Several variables are substituted at run-time:

 

  $nmbLookupPath      path to nmblookup ($Conf{NmbLookupPath})
  $host               NetBios name
    

 

In some cases you might need to change the broadcast address, for example if nmblookup uses 192.168.255.255 by default and you find that doesn't work, try 192.168.1.255 (or your equivalent class C address) using the -B option:

 

   $Conf{NmbLookupFindHostCmd} = '$nmbLookupPath -B 192.168.1.255 $host';
    

 

If you use a WINS server and your machines don't respond to multicast NetBios requests you can use this (replace 1.2.3.4 with the IP address of your WINS server):

 

   $Conf{NmbLookupFindHostCmd} = '$nmbLookupPath -R -U 1.2.3.4 $host';
    

 

This is preferred over multicast since it minimizes network traffic.

 

Experiment manually for your site to see what form of nmblookup command works.

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{FixedIPNetBiosNameCheck} = 0;

For fixed IP address hosts, BackupPC_dump can also verify the netbios name to ensure it matches the host name. An error is generated if they do not match. Typically this flag is off. But if you are going to transition a bunch of machines from fixed host addresses to DHCP, setting this flag is a great way to verify that the machines have their netbios name set correctly before turning on DCHP.

$Conf{PingPath} = '';

Full path to the ping command. Security caution: normal users should not be allowed to write to this file or directory.

 

If you want to disable ping checking, set this to some program that exits with 0 status, eg:

 

    $Conf{PingPath} = '/bin/echo';
    

$Conf{PingCmd} = '$pingPath -c 1 $host';

Ping command. The following variables are substituted at run-time:

 

  $pingPath      path to ping ($Conf{PingPath})
  $host          host name
    

 

Wade Brown reports that on solaris 2.6 and 2.7 ping -s returns the wrong exit status (0 even on failure). Replace with "ping $host 1", which gets the correct exit status but we don't get the round-trip time.

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{PingMaxMsec} = 20;

Maximum round-trip ping time in milliseconds. This threshold is set to avoid backing up PCs that are remotely connected through WAN or dialup connections. The output from ping -s (assuming it is supported on your system) is used to check the round-trip packet time. On your local LAN round-trip times should be much less than 20msec. On most WAN or dialup connections the round-trip time will be typically more than 20msec. Tune if necessary.

$Conf{CompressLevel} = 0;

Compression level to use on files. 0 means no compression. Compression levels can be from 1 (least cpu time, slightly worse compression) to 9 (most cpu time, slightly better compression). The recommended value is 3. Changing to 5, for example, will take maybe 20% more cpu time and will get another 2-3% additional compression. See the zlib documentation for more information about compression levels.

 

Changing compression on or off after backups have already been done will require both compressed and uncompressed pool files to be stored. This will increase the pool storage requirements, at least until all the old backups expire and are deleted.

 

It is ok to change the compression value (from one non-zero value to another non-zero value) after dumps are already done. Since BackupPC matches pool files by comparing the uncompressed versions, it will still correctly match new incoming files against existing pool files. The new compression level will take effect only for new files that are newly compressed and added to the pool.

 

If compression was off and you are enabling compression for the first time you can use the BackupPC_compressPool utility to compress the pool. This avoids having the pool grow to accommodate both compressed and uncompressed backups. See the documentation for more information.

 

Note: compression needs the Compress::Zlib perl library. If the Compress::Zlib library can't be found then $Conf{CompressLevel} is forced to 0 (compression off).

$Conf{ClientTimeout} = 72000;

Timeout in seconds when listening for the transport program's (smbclient, tar etc) stdout. If no output is received during this time, then it is assumed that something has wedged during a backup, and the backup is terminated.

 

Note that stdout buffering combined with huge files being backed up could cause longish delays in the output from smbclient that BackupPC_dump sees, so in rare cases you might want to increase this value.

 

Despite the name, this parameter sets the timeout for all transport methods (tar, smb etc).

$Conf{MaxOldPerPCLogFiles} = 12;

Maximum number of log files we keep around in each PC's directory (ie: pc/$host). These files are aged monthly. A setting of 12 means there will be at most the files LOG, LOG.0, LOG.1, ... LOG.11 in the pc/$host directory (ie: about a years worth). (Except this month's LOG, these files will have a .z extension if compression is on).

 

If you decrease this number after BackupPC has been running for a while you will have to manually remove the older log files.

$Conf{DumpPreUserCmd} = undef;

$Conf{DumpPostUserCmd} = undef;

$Conf{DumpPreShareCmd} = undef;

$Conf{DumpPostShareCmd} = undef;

$Conf{RestorePreUserCmd} = undef;

$Conf{RestorePostUserCmd} = undef;

$Conf{ArchivePreUserCmd} = undef;

$Conf{ArchivePostUserCmd} = undef;

Optional commands to run before and after dumps and restores, and also before and after each share of a dump.

 

Stdout from these commands will be written to the Xfer (or Restore) log file. One example of using these commands would be to shut down and restart a database server, dump a database to files for backup, or doing a snapshot of a share prior to a backup. Example:

 

   $Conf{DumpPreUserCmd} = '$sshPath -q -x -l root $host /usr/bin/dumpMysql';
    

 

The following variable substitutions are made at run time for $Conf{DumpPreUserCmd}, $Conf{DumpPostUserCmd}, $Conf{DumpPreShareCmd} and $Conf{DumpPostShareCmd}:

 

       $type         type of dump (incr or full)
       $xferOK       1 if the dump succeeded, 0 if it didn't
       $client       client name being backed up
       $host         host name (could be different from client name if
                                $Conf{ClientNameAlias} is set)
       $hostIP       IP address of host
       $user         user name from the hosts file
       $moreUsers    list of additional users from the hosts file
       $share        the first share name (or current share for
                       $Conf{DumpPreShareCmd} and $Conf{DumpPostShareCmd})
       $shares       list of all the share names
       $XferMethod   value of $Conf{XferMethod} (eg: tar, rsync, smb)
       $sshPath      value of $Conf{SshPath},
       $cmdType      set to DumpPreUserCmd or DumpPostUserCmd
    

 

The following variable substitutions are made at run time for $Conf{RestorePreUserCmd} and $Conf{RestorePostUserCmd}:

 

       $client       client name being backed up
       $xferOK       1 if the restore succeeded, 0 if it didn't
       $host         host name (could be different from client name if
                                $Conf{ClientNameAlias} is set)
       $hostIP       IP address of host
       $user         user name from the hosts file
       $moreUsers    list of additional users from the hosts file
       $share        the first share name
       $XferMethod   value of $Conf{XferMethod} (eg: tar, rsync, smb)
       $sshPath      value of $Conf{SshPath},
       $type         set to "restore"
       $bkupSrcHost  host name of the restore source
       $bkupSrcShare share name of the restore source
       $bkupSrcNum   backup number of the restore source
       $pathHdrSrc   common starting path of restore source
       $pathHdrDest  common starting path of destination
       $fileList     list of files being restored
       $cmdType      set to RestorePreUserCmd or RestorePostUserCmd
    

 

The following variable substitutions are made at run time for $Conf{ArchivePreUserCmd} and $Conf{ArchivePostUserCmd}:

 

       $client       client name being backed up
       $xferOK       1 if the archive succeeded, 0 if it didn't
       $host         Name of the archive host
       $user         user name from the hosts file
       $share        the first share name
       $XferMethod   value of $Conf{XferMethod} (eg: tar, rsync, smb)
       $HostList     list of hosts being archived
       $BackupList   list of backup numbers for the hosts being archived
       $archiveloc   location where the archive is sent to
       $parfile      amount of parity data being generated (percentage)
       $compression  compression program being used (eg: cat, gzip, bzip2)
       $compext      extension used for compression type (eg: raw, gz, bz2)
       $splitsize    size of the files that the archive creates
       $sshPath      value of $Conf{SshPath},
       $type         set to "archive"
       $cmdType      set to ArchivePreUserCmd or ArchivePostUserCmd
    

 

Note: all Cmds are executed directly without a shell, so the prog name needs to be a full path and you can't include shell syntax like redirection and pipes; put that in a script if you need it.

$Conf{UserCmdCheckStatus} = 0;

Whether the exit status of each PreUserCmd and PostUserCmd is checked.

 

If set and the Dump/Restore/Archive Pre/Post UserCmd returns a non-zero exit status then the dump/restore/archive is aborted. To maintain backward compatibility (where the exit status in early versions was always ignored), this flag defaults to 0.

 

If this flag is set and the Dump/Restore/Archive PreUserCmd fails then the matching Dump/Restore/Archive PostUserCmd is not executed. If DumpPreShareCmd returns a non-exit status, then DumpPostShareCmd is not executed, but the DumpPostUserCmd is still run (since DumpPreUserCmd must have previously succeeded).

 

An example of a DumpPreUserCmd that might fail is a script that snapshots or dumps a database which fails because of some database error.

$Conf{ClientNameAlias} = undef;

Override the client's host name. This allows multiple clients to all refer to the same physical host. This should only be set in the per-PC config file and is only used by BackupPC at the last moment prior to generating the command used to backup that machine (ie: the value of $Conf{ClientNameAlias} is invisible everywhere else in BackupPC). The setting can be a host name or IP address, eg:

 

        $Conf{ClientNameAlias} = 'realHostName';
        $Conf{ClientNameAlias} = '192.1.1.15';
    

 

will cause the relevant smb/tar/rsync backup/restore commands to be directed to realHostName, not the client name.

 

Note: this setting doesn't work for hosts with DHCP set to 1.

Email reminders, status and messages¶

$Conf{SendmailPath} = '';

Full path to the sendmail command. Security caution: normal users should not allowed to write to this file or directory.

$Conf{EMailNotifyMinDays} = 2.5;

Minimum period between consecutive emails to a single user. This tries to keep annoying email to users to a reasonable level. Email checks are done nightly, so this number is effectively rounded up (ie: 2.5 means a user will never receive email more than once every 3 days).

$Conf{EMailFromUserName} = '';

Name to use as the "from" name for email. Depending upon your mail handler this is either a plain name (eg: "admin") or a fully-qualified name (eg: "admin@mydomain.com").

$Conf{EMailAdminUserName} = '';

Destination address to an administrative user who will receive a nightly email with warnings and errors. If there are no warnings or errors then no email will be sent. Depending upon your mail handler this is either a plain name (eg: "admin") or a fully-qualified name (eg: "admin@mydomain.com").

$Conf{EMailUserDestDomain} = '';

Destination domain name for email sent to users. By default this is empty, meaning email is sent to plain, unqualified addresses. Otherwise, set it to the destintation domain, eg:

 

   $Cong{EMailUserDestDomain} = '@mydomain.com';
    

 

With this setting user email will be set to 'user@mydomain.com'.

$Conf{EMailNoBackupEverSubj} = undef;

$Conf{EMailNoBackupEverMesg} = undef;

This subject and message is sent to a user if their PC has never been backed up.

 

These values are language-dependent. The default versions can be found in the language file (eg: lib/BackupPC/Lang/en.pm). If you need to change the message, copy it here and edit it, eg:

 

  $Conf{EMailNoBackupEverMesg} = <<'EOF';
  To: $user$domain
  cc:
  Subject: $subj
  Dear $userName,
  This is a site-specific email message.
  EOF
    

$Conf{EMailNotifyOldBackupDays} = 7.0;

How old the most recent backup has to be before notifying user. When there have been no backups in this number of days the user is sent an email.

$Conf{EMailNoBackupRecentSubj} = undef;

$Conf{EMailNoBackupRecentMesg} = undef;

This subject and message is sent to a user if their PC has not recently been backed up (ie: more than $Conf{EMailNotifyOldBackupDays} days ago).

 

These values are language-dependent. The default versions can be found in the language file (eg: lib/BackupPC/Lang/en.pm). If you need to change the message, copy it here and edit it, eg:

 

  $Conf{EMailNoBackupRecentMesg} = <<'EOF';
  To: $user$domain
  cc:
  Subject: $subj
  Dear $userName,
  This is a site-specific email message.
  EOF
    

$Conf{EMailNotifyOldOutlookDays} = 5.0;

How old the most recent backup of Outlook files has to be before notifying user.

$Conf{EMailOutlookBackupSubj} = undef;

$Conf{EMailOutlookBackupMesg} = undef;

This subject and message is sent to a user if their Outlook files have not recently been backed up (ie: more than $Conf{EMailNotifyOldOutlookDays} days ago).

 

These values are language-dependent. The default versions can be found in the language file (eg: lib/BackupPC/Lang/en.pm). If you need to change the message, copy it here and edit it, eg:

 

  $Conf{EMailOutlookBackupMesg} = <<'EOF';
  To: $user$domain
  cc:
  Subject: $subj
  Dear $userName,
  This is a site-specific email message.
  EOF
    

$Conf{EMailHeaders} = <<EOF;

Additional email headers. This sets to charset to utf8.

CGI user interface configuration settings¶

$Conf{CgiAdminUserGroup} = '';

$Conf{CgiAdminUsers} = '';

Normal users can only access information specific to their host. They can start/stop/browse/restore backups.

 

Administrative users have full access to all hosts, plus overall status and log information.

 

The administrative users are the union of the unix/linux group $Conf{CgiAdminUserGroup} and the manual list of users, separated by spaces, in $Conf{CgiAdminUsers}. If you don't want a group or manual list of users set the corresponding configuration setting to undef or an empty string.

 

If you want every user to have admin privileges (careful!), set $Conf{CgiAdminUsers} = '*'.

 

Examples:

 

   $Conf{CgiAdminUserGroup} = 'admin';
   $Conf{CgiAdminUsers}     = 'craig celia';
   --> administrative users are the union of group admin, plus
     craig and celia.
   $Conf{CgiAdminUserGroup} = '';
   $Conf{CgiAdminUsers}     = 'craig celia';
   --> administrative users are only craig and celia'.
    

$Conf{CgiURL} = undef;

URL of the BackupPC_Admin CGI script. Used for email messages.

$Conf{Language} = 'en';

Language to use. See lib/BackupPC/Lang for the list of supported languages, which include English (en), French (fr), Spanish (es), German (de), Italian (it), Dutch (nl), Polish (pl), Portuguese Brazillian (pt_br) and Chinese (zh_CH).

 

Currently the Language setting applies to the CGI interface and email messages sent to users. Log files and other text are still in English.

$Conf{CgiUserHomePageCheck} = '';

$Conf{CgiUserUrlCreate} = 'mailto:%s';

User names that are rendered by the CGI interface can be turned into links into their home page or other information about the user. To set this up you need to create two sprintf() strings, that each contain a single '%s' that will be replaced by the user name. The default is a mailto: link.

 

$Conf{CgiUserHomePageCheck} should be an absolute file path that is used to check (via "-f") that the user has a valid home page. Set this to undef or an empty string to turn off this check.

 

$Conf{CgiUserUrlCreate} should be a full URL that points to the user's home page. Set this to undef or an empty string to turn off generation of URLs for user names.

 

Example:

 

   $Conf{CgiUserHomePageCheck} = '/var/www/html/users/%s.html';
   $Conf{CgiUserUrlCreate}     = 'http://myhost/users/%s.html';
   --> if /var/www/html/users/craig.html exists, then 'craig' will
     be rendered as a link to http://myhost/users/craig.html.
    

$Conf{CgiDateFormatMMDD} = 1;

Date display format for CGI interface. A value of 1 uses US-style dates (MM/DD), a value of 2 uses full YYYY-MM-DD format, and zero for international dates (DD/MM).

$Conf{CgiNavBarAdminAllHosts} = 1;

If set, the complete list of hosts appears in the left navigation bar pull-down for administrators. Otherwise, just the hosts for which the user is listed in the host file (as either the user or in moreUsers) are displayed.

$Conf{CgiSearchBoxEnable} = 1;

Enable/disable the search box in the navigation bar.

$Conf{CgiNavBarLinks} = [ ... ];

Additional navigation bar links. These appear for both regular users and administrators. This is a list of hashes giving the link (URL) and the text (name) for the link. Specifying lname instead of name uses the language specific string (ie: $Lang->{lname}) instead of just literally displaying name.

$Conf{CgiStatusHilightColor} = { ...

Hilight colors based on status that are used in the PC summary page.

$Conf{CgiHeaders} = '<meta http-equiv="pragma" content="no-cache">';

Additional CGI header text.

$Conf{CgiImageDir} = '';

Directory where images are stored. This directory should be below Apache's DocumentRoot. This value isn't used by BackupPC but is used by configure.pl when you upgrade BackupPC.

 

Example:

 

    $Conf{CgiImageDir} = '/var/www/htdocs/BackupPC';
    

$Conf{CgiExt2ContentType} = { };

Additional mappings of file name extenions to Content-Type for individual file restore. See $Ext2ContentType in BackupPC_Admin for the default setting. You can add additional settings here, or override any default settings. Example:

 

    $Conf{CgiExt2ContentType} = {
                'pl'  => 'text/plain',
         };
    

$Conf{CgiImageDirURL} = '';

URL (without the leading http://host) for BackupPC's image directory. The CGI script uses this value to serve up image files.

 

Example:

 

    $Conf{CgiImageDirURL} = '/BackupPC';
    

$Conf{CgiCSSFile} = 'BackupPC_stnd.css';

CSS stylesheet "skin" for the CGI interface. It is stored in the $Conf{CgiImageDir} directory and accessed via the $Conf{CgiImageDirURL} URL.

 

For BackupPC v3.x several color, layout and font changes were made. The previous v2.x version is available as BackupPC_stnd_orig.css, so if you prefer the old skin, change this to BackupPC_stnd_orig.css.

$Conf{CgiUserConfigEditEnable} = 1;

Whether the user is allowed to edit their per-PC config.

$Conf{CgiUserConfigEdit} = { ...

Which per-host config variables a non-admin user is allowed to edit. Admin users can edit all per-host config variables, even if disabled in this list.

 

SECURITY WARNING: Do not let users edit any of the Cmd config variables! That's because a user could set a Cmd to a shell script of their choice and it will be run as the BackupPC user. That script could do all sorts of bad things.

Version Numbers¶

Author¶

Copyright¶

Credits¶

License¶