Obnam makes backups. Backups can be stored on local hard disks, or online via the SSH SFTP protocol. The backup server, if used, does not require any special software, on top of SSH.

* Snapshot backups. Every generation looks like a complete snapshot, so you
don't need to care about full versus incremental backups, or rotate real
or virtual tapes.
* Data de-duplication, across files, and backup generations. If the backup
repository already contains a particular chunk of data, it will be re-used,
even if it was in another file in an older backup generation. This way, you
don't need to worry about moving around large files, or modifying them.
* Encrypted backups, using GnuPG.
* Push or pull operation, depending on what you need. You can run Obnam on
the client, and push backups to the server, or on the server, and pull
from the client over SFTP.