A big thanks to Čolović Vladan for his post at http://www.cvladan.com/misc/list-of-free-linux-backup-solutions.html

Here is his list (and mostly his comments) with a few additions:

Based on rsync:

• rsnapshot : Written in Perl, using rsync and hard links, it is possible to keep multiple, full backups instantly available
• rsback : Written in Perl, I am not sure what are the differences from rsnapshot
• drsync : a Perl wrapper for rsync which keeps track of the filelist between synchronizations. If you delete a file in one place, it will delete it in the other place; if you add a file, it copies to the other place.
• ccollect : Written in simple sh-script.
• fwbackups : Installable with yum (yum install fwbackups).
• flyback : A Google Code, Python based project. The Google Group is still active in Feb 2009, but some people seem to think this project is dead.
• Dirvish : I am currently using Dirvish and it works well. It does what it was designed to do.
• rsync-backup : Perl script.
• RIBS (Rsync Incremental Backup Script) : Written in PHP.
• rsnap : Python.
• TimeVault : Timevault is a graphical configuration utility (that creates cron jobs for rsync?). Similar to FlyBack. It integrates with Nautilus seamlessly.
• Back In Time : Back In Time is a simple backup system for Linux inspired from “flyback project” and “TimeVault”. The backup is done by taking snapshots of a specified set of directories. Back In Time is just a GUI. The real magic is done by rsync (take snapshots and restore), diff (check if somethind changed) and cp (make hardlinks).

Based on rdiff:

• rdiff-backup : Python & C written. Best documentation at this wiki. Can be installed with yum.
• SafeKeep : Python / based on rdiff-backup. Installable on Ubuntu with a deb package. SafeKeep is a centralized and easy to use backup application that combines the best features of a mirror and an incremental backup.
• Backupninja : centralized way to configure and schedule many different backup utilities.
• pybackpack : Python, based on rdiff-backup. Basic usage at howtoforge.com. Can be installed with yum (yum install pybackpack). But, it has a big problem in not possible to start it from the commandline or cron.
• rBackup : Written mainly in PHP. Not in repository.

None of the above:

• Areca : Written in Java, supports everything I need. Not available in any Fedora repository. Good tutorial and manuals, but still the problem that it is not diff-based (the whole file is written). Good solution is because it has a compression.
• Clonezilla Live : Clonezilla Live can be used to clone individual computers using a CD/DVD or USB flash drive.
• RESTORE-EE (Enterprise Edition) : Complicated and nice, but not impressed. Tutorial at howtoforge.
• Duplicity : Very good, only with no GUI or other tool for restoring data. Probably the only viable solution if you backup data is on a public server, because supports encryption right from the start.
• Backerupper : To me, it looks that is not maintained anymore. Written in Lazarus-Freepascal (Delphi for Linux)
• Bacula : Really heavy. Bacula is a set of computer programs that permits the system administrator to manage backup, recovery, and verification of computer data across a network of computers of different kinds.
• Amanda : Claims to fit a range of . Here are some blog posts about backing up with Amanda. See also zmanda recovery manager.
• Mondo Rescue : Really a recovery solution, but just to mention it.
• afbackup : Written in C. Very old and mature, but none of the documentation.
• Konserve : GUI (KDE) app that sits in the system tray and backs up any directory to any other directory (including a remote network repository or FTP site) in the form of an industry-standard .tar.gz archive. Good reviews. (May be a front end for rdiff.)
• ZFS snapshot visualization in GNOME : only for ZFS snapshots
• unison : allows two replicas of a collection of files and directories to be stored on different hosts (or different disks on the same host), modified separately, and then brought up to date by propagating the changes in each replica to the other.
• LVM Snapshots: use to ensure that the data that goes onto the backup destination is consistent.
• mylvmbackup : mylvmbackup is a tool for quickly creating backups of a MySQL server's data files.
• FSArchiver: claims to be "a very flexible program. FSArchiver can extract an archive to a partition which is smaller that the original one as long as there is enough space to store the data. It can also restore the data on a different file-system, so it can use it when you want to convert your file-system: you can backup an ext3 file-system, and restore it as a reiserfs."
• BackupPC : Docs say, "A clever pooling scheme minimizes disk storage and disk I/O. Identical files across multiple backups of the same or different PCs are stored only once resulting in substantial savings in disk storage and disk I/O. BackupPC is written in Perl and extracts backup data via SMB using Samba, tar over ssh/rsh/nfs, or rsync. It is robust, reliable, well documented and freely available as Open Source on SourceForge." BackupPC is a high-performance, enterprise-grade system for backing up Linux, Windows, and MacOS-X PCs and laptops to a server's disk.
• Link-Backup : Has the very powerful feature of intelligently handling renames, moves, and duplicate files without additional storage or transfer. Very few solutions offer this feature.
• StoreBackup : The third of 3 choices that intelligently handle renames and moves. "Copying and renaming of files or directories takes only the storage space of the hard links." See http://linuxfocus.org/English/January2004/article321.shtml

Others (todo):

• pdumpfs
• glastree
• Kamion

rsync Backup Resources

rsync backup recipes - http://www.mikerubel.org/computers/rsync_snapshots/

incremental backups with rdiff - http://www.gnu.org/savannah-checkouts/non-gnu/rdiff-backup/

rsync incremental backup script - http://www.rustyparts.com/ribs.php

official rsync examples - http://samba.anu.edu.au/rsync/examples.html

rsync backup documentation written by Kevin Korb - http://www.sanitarium.net/golug/rsync_backups.html

From "Free Backup Software" at http://www.backupcentral.com/components/com_mambowiki/index.php/Category...

And thanks to diaa for this info on compressed filesystem / file system compression