Alexander Spanke (heh) also suggested using Amanda. Amanda is an amazing tool, but another program called Bacula beats it hands-down.
Both utilities have an option for incremental backups, which is what you might also want to consider if using DVDs. Take one initial huge backup, and weekly, create a new incremental backup. Doing this, you won't have to store 20+ gigs each time. It's up to you to decide if this server grows more than 4.7G per each backup period.
I'm also a bacula fan. I do a "differential" dump every weekend (all changed files since last "full" dump) and incremental dumps every night (I'm backing up 3 machines). I have bacula write to 500MB files on a machine with a DVD writer. When I've got enough of these 500MB files to fill a DVD, I write a DVD. DVD media are very cheap indeed and I end up getting most files backed up on several different DVDs over a period of time. I'm very happy with this solution to my backup needs.
Moreover, bacula keeps a database of backed-up files and I can pretty easily recover a specific file from a specific date if I need to; bacula will tell me which volume the file is on and will recover if for me from that volume when I've loaded it.
Paul.
