> That sounds like more work than a persistent dirty bitmap. The advantage is > that > while dirty bitmaps are consumed by a single user, the Merkle tree can be used > to sync up any number of replicas.
I also consider it safer, because you make sure the data exists (using hash keys like SHA1). I am unsure how you can check if a dirty bitmap contains errors, or is out of date? Also, you can compare arbitrary Merkle trees, whereas a dirty bitmap is always related to a single image. (consider the user remove the latest backup from the backup target).
