Abstract: A cluster network is disclosed that includes a set of nodes coupled to a storage enclosure. The storage enclosure includes an arbiter for managing contention for ownership of the storage drives of the storage enclosure. The arbiter receives ownership commands and arbitrates the ownership of the storage drives on the basis of the commands and the current ownership settings of the affected storage drives. The arbiter is coupled to the SAS expander or multiplexer in the storage enclosure that routes communications to each of the storage drives of the storage enclosure.

Abstract: A network and a method for network operation are disclosed that facilitates the identification of a failure in the storage subsystem of the network and the recovery from such a failure. The storage subsystem includes storage enclosures that are coupled to each of the server nodes of the network. When a server node determines that it can no longer access a drive of the storage enclosure, the server node notifies the alternate server node of the network, which attempts to access the drive. If the alternate server node of the network can access the drive, the ownership of the logical unit that includes the drive is transferred to the alternate server node.

Abstract: A system and method for recovering from a drive failure in a storage array is disclosed in which a spare drive array is provided in the event of a failure in one of the active drives of the storage array. The spare drive array is comprised of multiple drives that are comprised in a RAID 0 configuration to reduce the time required to rebuild the content of the failed drive on the spare drive.

Abstract: A system, method and software for enhancing a redundant array of independent disks (RAID) rebuild process are provided. In association with the RAID, one or more bit maps is maintained corresponding to one or more data blocks of the RAID. During input/output (I/O) operations directed to the RAID, the I/O operations are evaluated to determine whether an operation will modify a data block of the RAID. If a data block is to be modified by an I/O operation, the bit map is preferably marked to indicate which data blocks of the RAID are being modified. In the event of disk failure, the bit map may be referenced in association with a disk reconstruction process such that only those data block having been modified before disk failure are reconstructed and these data blocks having not been modified remain substantially free from reconstructive operations.

Abstract: A method for error correction in a storage array is provided in which a data section comprising multiple data stripes are read following an indication that a volume of the storage array is degraded. An evaluation is made as to whether the data of the data section has been compromised. The evaluation may be performed by an exclusive-OR checksum operation performed on the bits of the data section. If the data of the data section has not been compromised, a rebuild of the multiple data stripes in the affected volume is not required and is not performed. If the data of the data section has been compromised, a rebuild of the data of the data stripes of the evaluated data section is performed in the affected volume. This process continues until all of the data stripes of the storage array have been evaluated.

Abstract: A computer system has a ROM device containing two separately flashed areas. Each area contains a firmware image. From the factory, the two firmware images are identical. Each image also contains the executable code to flash an image area. The ROM also contains a “boot block” sector that makes decisions as to which of the firmware images is the “active” image and which is the “inactive” image. The active image is copied from the ROM to a RAM device and executed from RAM during normal system operation. The inactive image normally is not executed. The boot block sector also contains code that performs a checksum verification on the active image during initialization and, if the checksum fails, switches the active/inactive status of the two firmware images to make the previously inactive image the active image. With two firmware images, the system can recover from a power failure occurring while flashing the ROM because the other firmware image is still available.