It supports full, incremental and differential backups, as well as catalogs, and can write to a file or tape drive, basically a solid, simple, easy to use backup program. Perfect Backup Perfect Backup supports almost all Linux distributions and has crash recovery. It's pretty reliable. It might not be big enough, and they do fail, usually at the worst possible time. Harder to take offsite as well.
RAID is a viable option though.
Tape It's reliable, you can buy BIG tapes, tape carousels and tape robots, and they're getting cheap enough for almost everyone to own one. Floppies I'm not kidding, there are rumors some people still use these to backup data. It's a floppy. They go bad and are very small. Great for config files though.