> More accurately, rsnapshot (which is basically a frontend to rsync)
> tells rsync to do that; IIRC by passing --link-dest pointing at the
> previous backup target directory.
I've used a similar (tho hand-cooked) script running `rsync`.
I switched to Bup a few years ago and saw a significant reduction in the
size of my backups that is partly due to the deduplication *between*
machines (I backup several Debian machines to the same backup
repository) as well as because the deduplication occurs even when I move
files around (most obvious when I move directories filled with large
files like videos or music).
Another advantage I've notice with Bup is that my backups are done much
more quickly (because more of the work is done locally on the client
machines which have SSDs, there's a lot less network communication, and
much less work is done on the backup server which is a low-power machine
with spinning rust).
The great advantage of `rsync/rsnapshot` is that your backup is really
"live": you can go `grep` and `find` through it with ease. With Bup you
can theoretically do that as well (via `bup fuse`) but the performance
is significantly lower :-(
Stefan
