Patent ID: 8161007

Claim:
A storage system for improving efficiency of a transmission of data identifiers, comprising: a processor of a source storage system configured to execute a storage operating system to record data changes as a set of changed data to one or more entries of a log, the log configured to indicate by a first identifier which data of the set of changed data of the source storage system has been allocated and then deleted between two discrete consistency points and indicate by a second identifier which data of the set of changed data has not been allocated and then deleted between the two discrete consistency points, wherein the data changes occur between a first persistent consistency point image (PCPI) and a second PCPI; the source storage system configured to scan the log to determine the data indicated by the first identifier and to determine the data indicated by the second identifier; the source storage system further configured to, in response to the scan of the log, transmit to a destination storage system the data indicated by the second identifier, and further configured to omit from transmission to the destination storage system the data indicated by the first identifier; and the destination storage system configured to store the data indicated by the second identifier.