Bacula is a set of Open Source, 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. Bacula is relatively easy to use and very efficient, while offering many advanced storage management features that make it easy to find and recover lost or damaged files. In technical terms, it is an Open Source, network based backup program. Download Bacula.
According to Source Forge statistics (rank and downloads), Bacula is by far the most popular Open Source backup program.