rdiff-backup is a simple backup tool which can be used locally and
remotely, on Linux and Windows, and even cross-platform between both.
Users have reported using it successfully on FreeBSD and MacOS X.

Beside its ease of use, one of the main advantages of rdiff-backup is
that it does use the same efficient protocol as rsync to transfer and
store data. Because rdiff-backup only stores the differences from the
previous backup to the next one (a so called reverse incremental
backup), the latest backup is always a full backup, making it easiest
and fastest to restore the most recent backups, combining the space
advantages of incremental backups while keeping the speed advantages
of full backups (at least for recent ones).

If the optional (runtime) dependencies pylibacl and pyxattr are
installed, rdiff-backup will support Access Control Lists and Extended
Attributes provided the file system(s) also support these features.

IMPORTANT: rdiff-backup 2.x is wire-incompatible with versions 1.x, for
local backups there's no problem but if you backup remotely you have to
use the same version of rdiff-backup in the client and server.