Efficient cloud storage systems, methods, and media are provided herein. Exemplary methods may include locating a Merkle tree of a stored object on a deduplicating block store, comparing an object at a source location to the Merkle tree of the stored object, determining changed blocks for the object at a source location, and transmitting a message across a network to the deduplicating block store, the message including the change blocks and Merkle nodes that correspond to the change blocks.