Method and system for transferring delta difference data to a storage device

摘要

A method and system for transferring difference data (delta) between new and old data from a data transferring unit to a storage device having a copy of the old data for enabling the storage device to determine the new data based on the old data and the transferred difference data and then store the new data in place of the old data. Both of the data transferring unit and the target storage device have a copy of the old data. When new data is written at the data transferring unit to modify the old data the data transferring unit compares the new data with the old data to determine the difference data. The difference data is indicative of the differences between the new data and the old data. The target storage device merges the old data with the difference data to determine the new data. Upon determining the new data the target storage device discards the old data and stores the new data. The method and system may be used with peer-to-peer remote copy (PPRC) storage systems and storage area network (SAN) storage systems.