Abstract: A method for memory page erasure-correcting property generation in a storage array includes dividing data into multiple stripes for storage in a storage array including multiple storage devices with a topology of a hypercube of a dimension t?3. The storage devices in same hypercubes of dimension t?1 including the hypercube of dimension t have even parity. An intersection of two non-parallel planes in the hypercube topology is a line, and each point along a line is a storage device in the storage array. Erasure-correcting properties are generated for the data using three nested codes, wherein a first nested code has even parity over planes of class 0, 1 and 2, a second nested code has a first global parity, and a third nested code has a second global parity and a third global parity.

Abstract: A method for memory page erasure-correcting property generation in a storage array includes dividing data into multiple stripes for storage in a storage array including multiple storage devices with a topology of a hypercube of a dimension t?3. The storage devices in same hypercubes of dimension t?1 including the hypercube of dimension t have even parity. An intersection of two non-parallel planes in the hypercube topology is a line, and each point along a line is a storage device in the storage array. Erasure-correcting properties are generated for the data using three nested codes, wherein a first nested code has even parity over planes of class 0, 1 and 2, a second nested code has a first global parity, and a third nested code has a second global parity and a third global parity.

Abstract: A method for memory page erasure reconstruction in a storage array includes dividing data into multiple stripes for storage in a storage array including multiple storage devices with a topology of a hypercube of a dimension t?3. The storage devices in same hypercubes of dimension t?1 including the hypercube of dimension t have even parity. An intersection of two non-parallel planes in the hypercube topology is a line, and each point along a line is a storage device in the storage array. A reconstructor processor reconstructs erased data for erased memory pages from non-erased data in the storage array by using parities in at least three dimensions based on the hypercube topology of the storage devices.

Abstract: A method for memory page erasure reconstruction in a storage array includes dividing data into multiple stripes for storage in a storage array including multiple storage devices with a topology of a hypercube of a dimension t?3. The storage devices in same hypercubes of dimension t?1 including the hypercube of dimension t have even parity. An intersection of two non-parallel planes in the hypercube topology is a line, and each point along a line is a storage device in the storage array. A reconstructor processor reconstructs erased data for erased memory pages from non-erased data in the storage array by using parities in at least three dimensions based on the hypercube topology of the storage devices.

Abstract: A data storage method comprises storing first data in at least a first data chunk, wherein the first data chunk is a logical representation of one or more sectors on at least a first disk drive in a storage system; storing first metadata, associated with the first data, in at least a first appendix, wherein the first appendix is a logical representation of a sector region on at least the first disk drive in the storage system, and wherein the first metadata comprises first atomicity metadata (AMD) and first validity metadata (VMD) associated with the first data; and storing a copy of the first VMD for the first data in at least one low latency non-volatile storage (LLNVS) device.

Abstract: A data storage method comprises storing first data in at least a first data chunk, wherein the first data chunk is a logical representation of one or more sectors on at least a first disk drive in a storage system; storing first metadata, associated with the first data, in at least a first appendix, wherein the first appendix is a logical representation of a sector region on at least the first disk drive in the storage system, and wherein the first metadata comprises first atomicity metadata (AMD) and first validity metadata (VMD) associated with the first data; and storing a copy of the first VMD for the first data in at least one low latency non-volatile storage (LLNVS) device.

Abstract: A bladed storage servicing system comprising a RAID layout facilitates the removal of one or more functional storage devices in a tray of the bladed storage subsystem in order to service a failed storage device. Upon removal of the tray from the bladed storage subsystem, the system designates the functional storage devices on the tray as temporarily removed. The system logs writes to the removed functional storage devices so that the functional storage devices can be returned to consistency when replaced in the bladed storage subsystem. The system manages reads to the removed functional storage devices through reconstruction from active storage devices in the bladed storage subsystem. Upon reinsertion of the tray in the bladed storage subsystem, the system verifies the identities of the functional storage devices and resynchronizes the functional storage devices to ensure data consistency.

Abstract: A fault-tolerant system for storage arrays that stored parity values both on separate disks from the data elements (horizontally aligned) and on the same disks as the data elements (vertically aligned), a so-called horizontal-vertical code or HoVer code. The fault-tolerant system has embodiments that are supported on a variety of array sizes and has significant flexibility in parameter selection. Certain embodiments can tolerate all combinations of T failed disks and, among those, some embodiments can tolerate many instances of more than T failures. The fault-tolerant system has efficient XOR-based encoding, recovery, and updating algorithms and has simple redundancy formulas.

Abstract: A system (and method) for determining reconstruction formulas for partial strip reconstruction in a storage system in which a plurality of lost strips have been detected, includes using a combination of a direct reconstruction method and a sequential reconstruction method.

Abstract: A system (and method) for a recovery of data from a lost sector in a storage system, which includes a set of readable and lost sectors in a plurality of disks in the storage system, includes identifying a lost sector of at least one disk of the storage system, determining whether the data from the lost sector is capable of being recovered, and, if the data from the lost sector is capable of being recovered, generating a recovery formula for the lost sector and recovering the data from the lost sector based on the recovery formula.

Abstract: A system for improving a performance of a write process in an exemplary RAID system reduces a number of IOs required for a short write in a RAID algorithm by using a replicated-parity drive. Parity is stored on the parity portion of the disk drives. A replicated-parity drive comprises all the parity information. Parity information for each parity drive is co-located or mirrored on the replicated-parity portion of the disk drives for fast access during a read portion of the read-modify-write process. Consequently, the system accesses parity data with one seek, as opposed to P seeks in a conventional disk array system utilizing P parity drives.

Abstract: A recovery enabling system for storage arrays is a high distance generalization of RAID-5 with optimal update complexity and near optimal storage efficiency. The recovery enabling system utilizes presets, data cells with known values that initialize the reconstruction process. The presets allow resolution of parity equations to reconstruct data when failures occur. In one embodiment, additional copies of the layout of the recovery enabling system are packed onto the same disks to minimize the effect of presets on storage efficiency without destroying the clean geometric construction of the recovery enabling system. The recovery enabling system has efficient XOR-based encoding, recovery, and updating algorithms for arbitrarily large distances, making the recovery enabling system an ideal candidate when storage-efficient reliable codes are required.

Abstract: A fault-tolerant system for storage arrays has constraints on the number of data from which each redundancy value is computed. The fault-tolerant system has embodiments that are supported on small array sizes to arbitrarily large array sizes, and can tolerate a large number T of failures. Certain embodiments can tolerate many instances of more than T failures. The fault-tolerant system has efficient XOR-based encoding, recovery, and updating algorithms and has simple redundancy formulas. The fault-tolerant system has improved IO seek costs for certain multiple-element sequential host updates.