Arkeia is a commercial Unix backup program.

There's a free version, Arkeia Light, which lets you back up one server and two clients, as long as you're not trying to back up NFS mounts. It's also free for commercial use which is kinda nice.

It is configured by an XFree86 application in which you define tapes, drives, pools, etc. You can also control almost everything with arkc, the command line client.

See ArkeiaNotes and BackupNotes.