Patent ID: 7478221

Claim:
A system comprising: a volume server; one or more physical storage devices including a first physical storage device; a front-end layer of virtualization participants, including a front-end virtualization participant; and a back-end layer of virtualization participants, including a first back-end virtualization participant; wherein each of said front-end layer of virtualization participants is configured to interact with one or more storage consumers to receive external storage requests from said one or more storage consumers, wherein said one or more storage consumers are external to said front-end layer and said back-end layer of virtualization participants; wherein each of said back-end layer of virtualization participants is configured to provide said volume server and other ones of said front-end and said back-end layers of virtualization participants with access to one or more of said physical storage devices, but is not directly accessible by said one or more storage consumers; wherein the volume server is configured to: aggregate storage in the one or more physical storage devices into a logical volume; and provide configuration information for the logical volume to the front-end virtualization participant and the first back-end virtualization participant, wherein the configuration information includes a generation identifier indicative of a version of the configuration information; wherein the front-end virtualization participant is configured to: send a first internal storage request including a target virtual address identifying a target block of the logical volume to the first back-end virtualization participant, wherein the first internal storage request includes a front-end generation identifier corresponding to a latest version of the configuration information available at the front-end virtualization participant; wherein the first back-end virtualization participant is configured to: use the configuration information to translate the target virtual address to a corresponding physical block address of the first physical storage device; and perform a first physical I/O operation on a first physical data block stored at the physical block address corresponding to the target virtual address.