I am looking for a simple backup solution for backing up my Linux server (RHEL5-x86_64).
I must be automatic (run at night, so I cannot baby-sit it)
It must be run on a live system (or semi-live - I expect performance to drop while backing up)
It must be able to send the back up to either local disk, FTP or other mountable drives.
Must support rotating backups so it does not eat up all available space.
A big bonus would be support for daily differential backup, with weekly full backup.
So far I have looked at dd, tar and Amanda.
Amanda seems unnecessary complicated and married to tapes (with virtual tapes on hard-disk - wtf?). dd and tar are nice and simple, but does not support easy differential backup and requires a fair bit of custom scripting to work smoothly.
Any constructive suggestions are very welcome!
edit: Just tried tar'ing / and the disk-files of the virtual machines i'm running gives the warning "file changed as we read it" - is that a problem?
edit2: @cjc - yes, the scenario is that the server catches fire. After setting up a new server (not time critical in this case) the backup should be transfered from an offsite FTP server and the machine should run as before the fire (or whatever went wrong). I would prefer not to have to install a new OS. I imagined using a Live Linux CD, install grub and copy backup to HDD as in this guide: http://ubuntuforums.org/showthread.php?t=35087