Backshift is a deduplicating (variable-sized, content-based blocks), compressing (xz or bz2) backup program. Full saves and incrementals are pretty indistinct other than the amount of data transmitted, somewhat like with "rsync --link-dest" but without the huge number of hardlinks. It also de-duplicates large file content at a granularity of about 2 megabytes on average; there tends to be a unique copy of each file with size less than around 2 megabytes on average.
