OK, so I took a quick look at various backup programs available for linux. This post is neither complete nor completely unbiased, as I already use obnam and am quite satisfied with it. I wanted to re-compare some alternatives anyway, but the other programs didn't even fit my feature requirements.
Gone unmaintained in 2015 and eventually got forked after not accepting community
contributions. Needs to be installed on the backup server, too.
Update: Domain attic-backup.org bacame unavailable in March 2021.
No deduplication available and you have to rotate the backups yourself.
Citing from bup's website:
'bup restore' can't pull directly from a remote server.
bup currently has no way to prune old backups.