rdiff-backup is a script that backs up one directory to another. The target directory ends up a copy of the source directory, but extra reverse diffs are stored in a special subdirectory of that target directory, so you can still recover files lost some time ago. The idea is to combine the best features of a mirror and an incremental backup. rdiff-backup also preserves subdirectories, hard links, dev files, permissions, uid/gid ownership (if it is running as root), and modification times. Finally, rdiff-backup can operate in a bandwidth efficient manner over a pipe, like rsync. Thus you can use rdiff-backup and ssh to securely back a hard drive up to a remote location, and only the differences will be transmitted. (source : description de la première version publiée)
Rdiff-backup has been around for almost 20 years now and has proved to be a very solid solution for backups and it is still unique in its model of unlimited incrementals with no need to space consuming regular full backups. (source : page d'accueil du site)
