For reference, here's the paper that describes the in-place update algo in rsync: https://www.usenix.org/legacy/events/usenix03/tech/freenix03/full_papers/rasch

For reference, here's the paper that describes the in-place update algo in rsync: https://www.usenix.org/legacy/events/usenix03/tech/freenix03/full_papers/rasch/rasch.pdf https://www.usenix.org/legacy/events/usenix03/tech/freenix03.... I haven't looked into it more deeply, but I think it's possible to apply the same idea to variable sized chunks. Also, most modern compression tools have an "rsyncable" option that makes the archives play more nicely with rsync.