Patent ID: 7275141

Claim:
In a data storage environment having a server, a first and second data storage volume, and production data being stored on the first data storage volume, and a copy of the production data, denominated as the data copy, being stored on the second data storage volume, a method, operable on a computer system, of handling updates to the data copy when the environment is configured for processing incremental updates to the data copy, the method comprising the steps of: protecting the data copy from being written over by designating a current tracking data structure as a transfer data structure and a current transfer data structure as a tracking data structure; responsive to the start of a full update to the copy of the production data, not marking the state of the production data as being ready for being copied; updating a session associated with the data copy as being in an inconsistent state with the data copy; completing the update to the copy of production data; and unprotecting the data copy after completion of the update by swapping the designation of the transfer and tracking structures and designating the transfer data structure as the current tracking data structure.