Patent ID: 7434093

Claim:
In a computing system including a primary computer system having a primary mass storage device where data blocks are stored and a backup computer system having a backup mass storage device where a backup copy of the data blocks is stored, a method for restoring data blocks that are lost at the primary mass storage device, the method comprising the acts of: after losing the data blocks at the primary mass storage device, receiving a first read request that would otherwise be processed by the primary computer system; transmitting the first read request to the backup computer system; as the backup computer system returns one or more data blocks from the backup mass storage device in response to the read request, writing the one or more data blocks to a mass storage device associated with the primary computer system; prior to a full copy of the data blocks of the backup mass storage device being restored to the mass storage device associated with the primary computer system, performing the acts of: receiving a second request, wherein the second read request is for at least one of the one or more data blocks that have been written to the mass storage device associated with the primary computer system; and responding to the second read request using the mass storage device associated with the primary computer system.