Open source Backup software

Amanda

Amanda is an open source computer archiving tool that is able to back up data residing on multiple computers on a network. (BSD)

Linux - FreeBSD

BackupPC

BackupPC is a high-performance, enterprise-grade system for backing up Linux, WinXX and MacOSX PCs and laptops to a server's disk. (GPL)

Linux - FreeBSD - Windows - MAC OS X

Bacula

Bacula is a set of computer programs that permit you to manage backup, recovery, and verification of computer data across a network of computers of different kinds. (GPL)

Linux - FreeBSD - Windows - MAC OS X

Clonezilla

Clonezilla is an open source clone system (OCS) solution with unicasting and multicasting. (GPL)

Linux - FreeBSD

FOG

FOG is a Linux-based, free and open source computer imaging solution for Windows XP, Vista and 7 that ties together a few open-source tools with a php-based web interface. (GPL)

Linux - Windows

Mondo Rescue

Mondo Rescue is a GPL disaster recovery solution. It supports Linux and FreeBSD. (GPL)

Linux - FreeBSD

6 applications