[rdiff-backup-users] Re: more info on 25gig files

[rsync2eran]

Hi,

Donovan Baarda wrote:
> There was a long discussion on the rsync lists about the best heuristic
> for blocksize and blocksum size (rsync also trims the strongsum size to
> make the signature smaller, and it was getting blocksum collisions on
> large files). I helped figure out the formula's for blocksize and
> blocksum size that rsync now uses.

There's a related issue we discussed a while ago:
One thing that's different between rsync and naive use of librsync (as
done by rdiff and, I think, rdiff-backup) is that the latter doesn't
have a strong full-size integrity check. With librsync's default 4-byte
checksums, using a small block size on a large file makes the
probability of silent corruption disturbingly non-negligible.

  Eran