Patent ID: 7203796

Claim:
A method of operating a destination storage server to mirror a primary volume maintained by a source storage server, the method comprising: receiving, at the destination storage server, a plurality of log entries from the source storage server, the plurality of log entries representing write requests received by the source storage server; writing the received log entries to a file maintained by the destination storage server; receiving, at the destination storage server, data from the source storage server during a synchronization phase of a consistency point, the consistency point being one of a plurality of regularly occurring consistency points, each characterized by the saving of data specified by write requests in a set of non-volatile storage devices managed by a RAID layer in the source storage server and in a set of non-volatile storage devices managed by a RAID layer in the destination storage server, wherein said data received at the destination storage server from the source storage server during the synchronization phase of the consistency point include volume block number updates from the source storage server; using the data received at the destination storage server from the source storage server during the synchronization phase of the consistency point, including the volume block number updates, to update a mirror volume maintained by the destination storage server, via the RAID layer in the destination storage server; and using log entries from the file to update the mirror volume.