Patent ID: 7831565

Claim:
A computer-implemented data storage volume rollback method, comprising: receiving, at a storage system controller, a request to rollback a master volume to a first snapshot; executing, by the controller, the rollback request; receiving, at the controller, a request to delete a second snapshot that contains data that will be copied to the master volume, wherein the second snapshot comprises at least one of a rollback snapshot and a most recent snapshot at a rollback point; separating, by the controller, the second snapshot into snapshot data and snapshot partition components; during execution of the rollback request, deleting the snapshot partition component of the second snapshot; and maintaining the snapshot data component of the second snapshot while the rollback of the master volume to the first snapshot is in progress, wherein the controller maintains the snapshot data component of the second snapshot by using address information of the second snapshot, wherein the address information is stored separately from the snapshot partition component of the second snapshot.