Patent ID: 7962780
Filing Date: 2011-06-14
Classification: G06F

Abstract:
1. A method to preserve data integrity between primary and secondary storage devices in a mirror and copy environment, the method comprising: receiving a write command from a host device, the write command having data associated therewith; writing the data to the primary storage device; attaching, by the primary storage device, a primary sequence number associated with the primary storage device to the write command, thereby providing a numbered write command with a command sequence number; transmitting, by the primary storage device, the numbered write command to a secondary storage device; comparing, by the secondary storage device, the command sequence number to a secondary sequence number associated with the secondary storage device; executing the numbered write command on the secondary storage device in the event the command sequence number matches the secondary sequence number; and ignoring the numbered write command on the secondary storage device in the event the command sequence number does not match the secondary sequence number.