Patent ID: 7293154

Claim:
A system comprising: a first and a second set of one or more storage devices; a virtual device client; and a virtual device server, wherein the virtual device server is configured to: aggregate storage in the first set of one or more storage devices into a virtual storage device; make the virtual storage device accessible to the virtual device client; wherein the virtual device client is operable to manage storage within the virtual storage device using a map identifying one or more in-use regions of the virtual storage device, wherein the map is maintained at a first software layer; wherein the virtual device server is further configured to: obtain the map identifying one or more in-use regions of the virtual storage device from the virtual device client in preparation for a synchronization operation; and perform the synchronization operation by copying data from the one or more in-use regions to the second set of one or more storage devices, wherein the synchronization operation is performed at a second software layer different than the first software layer, wherein the map is not visible at the second software layer.