udev

With hard disks getting larger by the month, keeping all your data backed up can be tricky. Raid will give you reliability, but no possibility of taking your data off-site, and tape drives are expensive.

I found myself needing to keep backups of an 80GB raid array for a small office server, and recalled an article I had read a few months ago in Linux Journal. The article details how you can keep snapshot backups of thumb drives on your harddisk... and that made me think doing the reverse should be workable too.