US Patent 9418131 Synchronization of volumes

In one aspect, a method to synchronize volumes includes comparing a first root hash of a root hash node in a first hash tree of a first volume with a second root hash of a second root hash node in a second hash tree of a second volume, for each child node of the first root hash node, comparing a hash of the child node with a hash of a corresponding node in the second hash tree if the first root hash and the second hash are not the same, for each hash in the first hash tree that does not match the corresponding hash in the second hash tree, determining if its node is a leaf node and copying the corresponding data block of the first volume to the corresponding data block of the second volume if a node is determined to be a leaf node.