US Patent 7610319 Efficient operations using assistance from secondary site

Efficient replication using assistance from a secondary node involves in one embodiment modifying data of a data volume at a primary node to create modified data. The primary node transmits the modified data to a first secondary node, wherein the first secondary node comprises a first replica of the data volume. The first secondary node receives and processes the modified data to generate processed data. The first secondary node transmits the processed data to the primary node. The primary node, in turn, receives and transmits the processed data to a second secondary node, wherein the second secondary node comprises a second replica of the data volume.