Snapshot copy of a secondary volume of a PPRC pair

Abstract

The present invention provides a method and apparatus for setting up a Peer-to-Peer Remote Copy (PPRC) session and snapshot copying a remote secondary volume to another volume on the remote subsystem. The apparatus includes a primary storage subsystem having a primary data-storage device with at least a primary volume. A primary processing unit relays a request to perform a snapshot copy of at least a portion of the primary volume to a secondary storage subsystem. The secondary storage subsystem includes a secondary data-storage device having a secondary volume which is maintained in a duplexed state with the primary volume through the use of remote copy sessions. A secondary processing unit, responsive to the relayed request can perform an equivalent of a snapshot copy of at least a portion of the primary volume by making a snapshot copy of a corresponding portion of the secondary volume.

Dependencies are inferred from the claim text.