Re: [Qemu-devel] [PATCH v3 0/8] block: drive-backup live backup command

[Benoît Canet]

I don't see the point of using hashes.
Using hashes means that at least one extra read will be done on the target to
compute the candidate target hash.
It's bad for a cloud provider where IOs count is a huge cost.

Another structure to replace a bitmap (smaller on the canonical case) would be
a block table as described in the Hystor paper:
www.cse.ohio-state.edu/~fchen/paper/papers/ics11.pdf

Best regards

Benoît