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BackupPC4AFS

BackupPC4AFS is deprecated and has been replaced by BackupAFS. This page is left only for reference.






















BackupPC4AFS allows BackupPC (currently at version 3.1.0) to backup OpenAFS volumes in addition to regular files. If you're not running OpenAFS, then you probably don't need this product.

Download BackupPC4AFS-3.0.0.2 now. Or check out the Screenshots first.

Installation and configuration instructions!

Changes:
v 0.01 - initial release.
v 0.02 - fixed minor perl annoyances.
v 0.03 - changed order of operations. Always create .backup volumes; this way, in the absence of any other backup product, we know that any volume without a recent .backup volume doesn't belong to any volumeset being dumped. Look at last update of .backup volume, not RW (Jeffrey Hutzelman, <jhutz@cmu.edu>, openafs-info, 2005-12-04). Deal with volumes that have "Never" been updated.
v 3.0.0 - Integrated former patch into regular BackupPC installer. Introduced new name, BackupPC4AFS. Upgraded code base to BackupPC-3.0.0 (full release). Modified AFS backup code to deal with pathnames > 80 characters. Better integration of VOS xfer method. Ability to configure AFS hosts via CGI. Updated and added installation and configuration documentation.
v 3.0.0.1 - Cosmetic fix for "vos examine" command in voswrap.pl. Updated logo.
v 3.0.0.2 - Fixed a bug in restore routine where the full dump would not be restored if exponential expiry were used and an intervening full dump had expired and been deleted.

Known issues:
The customizations to the restore interface currently only appear for English localization. Translations for other languages are happily accepted.

Background: AFS provides a native backup system to dump volumes directly to tape. It's good... for something designed in the 1980's. It's not quite so robust anymore. It's difficult to configure, is geared primarily to backup to tape, cannot back up volumes larger than your physical media, and usually requires quite a bit of homebrew scripting to make it work with modern media libraries.

In the search for a quality disk to disk backup solution for AFS, BackupPC was found, deemed conceptually good, and extended. In order to do this, several AFS concepts had to be mapped to BackupPC concepts. In AFS, volumes, not files, are the atomic units that may be backed up or restored. Similarly, volumes may live on any AFS fileserver within a given cell, and transparently moved at any time. In fact, this is one of the strengths of AFS.

Alternative Approaches: It is possible to back up files in AFS directly, using cp, tar, rsync, or any popular alternative. This does preserve data, but does not preserve the volume structure of the cell; filesystem ACLs, quotas, and volume mountpoints are all lost. Additionally, the backup agent must be able to read every file, which usually implies system:administrators membership, and accesses the files via the fileserver, thereby competing with users for fileserver resources.

By dumping volumes rather than files, we preserve all of the volume structure, including metadata. We do so by using vos commands to access the volume server, freeing the fileserver to continue processing user requests. Lastly, we create and dump AFS's .backup volumes so that there is no need to take volumes offline for dumping.

By dumping volumes using the AFS native "vos dump" command and storing the dump in a file, it can be restored manually (without BackupPC4AFS) if needed.

Alternative Products:

Applying the patch: The patch is already applied. Simply unpack the distribution into a temporary directory and run configure.pl as you would for any BackupPC installation.

Post-Installation Configuration: Installation and configuration instructions

Speed: When performing full backups of multi-gigabyte volumes, speeds of 24-35 megabytes per second are not uncommon over gigabit ethernet. BackupPC4AFS does take a few seconds to spawn and check output of vos commands. Also if a volumeset is very complex, computing the list of volumes may take several seconds. For these reasons, any incremental, full dumps of tiny volumes, and very complex volumeset definitions may show lower throughput.

Use: It is assumed that you're familiar with BackupPC and OpenAFS. If not, please become so before using this product. Admins should be aware of several caveats when backing up AFS:

When using BackupPC4AFS, several other changes must be noted. AFS has no real notion of hosts, therefore the "host" for AFS backups is really an abstract known as a "volumeset". Those of you who have used the AFS native backup utility will be familiar with this. In fact, we hijack the AFS volumeset AS the host. The "getvols.pl" script within BackupPC4AFS queries the AFS backup program for volumeset entries, then queries the volume location server to build a list of volumes.

Configuring volumesets for BackupPC is exactly identical to configuring volumesets for butc, the AFS native backup mechanism. In fact, there's nothing to stop you from using the same, or different, volumesets for the two backup mechanisms at the same time. If you absolutely hate the idea of storing a volumeset definition in the AFS backup db, then you need to replace "getvols.pl" with another method of turning a BackupPC host into a list of AFS volumes.

BackupPC conceptAFS concept
hostvolumeset
sharevolume
filevolume dump file
Screenshots:
 Editing the main config
 Editing the main config (hosts)
 Editing the main config (xfer)
 Browsing a backup
 Host Summary
 Summary
 Examining a logfile
 Restore

Disclaimer: This code is not presently supported, maintained, nor endorsed by the developers of BackupPC or OpenAFS. Any trademarks used are property of their respective owners.