1. A method for journaling operations modifying a primary storage, the method comprising: receiving a write request to modify data at a location in said primary storage; and journaling said write request in one of a plurality of partial journals, wherein each of said plurality of partial journals is emptied to a primary journal including one or more partial journal entries and one or more merged partial journal entries, each of the merged partial journal entries representing application of one or more data modifications for a time period to a location in primary storage.