Bacula - It comes by night and sucks the vital essence from your computers.
Bacula is a set of computer programs that permit you (or the system administrator) to manage backup, recovery, and verification of computer data across a network of computers of different kinds. In technical terms, it is a network client/server based backup program. Bacula is easy to use and efficient, while offering many advanced storage management features that make it easy to find and recover lost or damaged files. Bacula source code has been released under the GPL version 2 license.