Abstract: A method for revocable token identifiers may be employed in a shared storage environment. An access server may generate access tokens and include revocable token identifiers previously obtained from storage devices. When clients present access tokens to storage devices during storage requests, storage devices may check the validity of access tokens by verifying that the revocable token identifiers were previously issued to the access server. An access server may request that the storage device revoke revocable token identifiers. Storage devices may deny any future storage requests including revoked token identifiers. Additionally, an access token may include instructions specifying operations for a storage device to perform in conjunction with a storage request. A trusted server may issue grantor tokens granting permissions for access servers to use when issuing access tokens. An access server may then include such a grantor token in access tokens that it generates and issues to clients.

Abstract: A system using consistent virtual addresses to communicate in cooperative multi-layer virtualization environments includes a volume server, one or more physical storage devices, a front-end layer and a back-end layer of virtualization participants. The volume server may be configured to aggregate storage in the one or more physical storage devices into a logical volume, and to provide configuration information on the logical volume to a front-end virtualization participant and to a back-end virtualization participant. The front-end virtualization participant may be configured to send a storage request including a target virtual address identifying a block of the logical volume to the back-end virtualization participant. The back-end virtualization participant may be configured to use the configuration information to identify a physical data block at a physical storage device corresponding to the target virtual address, and to perform a physical I/O operation on the physical data block.

Abstract: A system for write forwarding in a storage environment employing distributed virtualization includes a first and a second storage server providing access to a first and a second physical storage device, respectively, a virtual device server and a virtual device client. The virtual device server may be configured to aggregate storage in the first and second physical storage device into a virtual storage device and make the virtual storage device accessible to the virtual device client for I/O operations. An update requested by the virtual device client may require a first physical write operation at the first physical storage device and a second physical write operation at the second physical device. The virtual device client may be configured to send an update request to the first storage server, rather than to both the first and the second storage servers.