It is always best to backup to another medium, be it a different local harddisk or a NFS mounted filesystem or use the remote backup capabilities to securely copy the backup to another system all together.
There is one wrapper script for rdup to make backups. This is rdup-simple. It uses a hardlinked backup scheme where each day has its own directory. This wrapper calls; rdup, rdup-snap and rdup-snap-link. It further more supports encryption, compressions and remote backups. This works by inserting the apropiate rdup helper utility in the pipeline.
When using rdup-simple the backup process consists out of two phases. During phase one a copy is made of any previous backups backups. This a hardlinked copy, meaning that it will take up very little space. It uses GNU cp to make this copy. See the manual page of rdup-snap-link for more information. rdup-simple uses ~/.rdup as the directory to write its internal filelist and timestamp file.
In phase two, rdup-simple will only update the files that are changed since the last backup. For these files the hardlink is removed or overwritten with a new version of the file. The net result is that each backup represents a complete view of your filesystem.
With rdup-simple you have a full view on what your filesystem looked like at any specific date. I personly keep about 3 months of backups and I can go back to any specific date in that time frame.
Backing up my homedir to the backup directory:
This will create a backup in /vol/backup/$HOSTNAME/200705/15. So each day will have its own directory. Multiple sources are allowed, so:
Will backup your homedirectory, /etc and /var/lib to the backup location. Also if you need to compress your backup, simple add a '-z' switch:
Dumping my homedir to the remote server:
The syntax is almost identical only the destination starts with the magic string 'ssh://'. Compression and encryption are just as easily enabled as with a local backup, just add '-z' and/or a '-k keyfile' argument:
In principle a restore is as easy as using the standard system tools to copy a directory to another location. However when the -a flag is used extended attributes are set, these are normally not read by the unix utilities. In this case you should restore by using rdup-cp to copy the files to another location. But there is also a script that can be used: rdup-restore.
And ofcourse the compression and encryption also works here, so to restore a compressed backup you need only to add the 'z' flag:
Compression and encryption will work as expected.