Triple parity technique for enabling efficient recovery from triple failures in a storage array
First Claim
1. A method for enabling recovery from three concurrent failures of storage devices in a storage array, comprising:
- executing, by a processor, a storage operating system of a computer;
determining, by the storage operating system, that three storage devices of the storage array have concurrently failed; and
in response to determining that the three storage devices have concurrently failed, executing, by the storage operating system, a triple parity recovery technique, wherein the triple parity recovery technique includes the storage operating system computing a diagonal parity block on a diagonal parity storage device of the storage array and an anti-diagonal parity block on an anti-diagonal parity storage device of the storage array that were not previously stored for the three failed storage devices.
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Abstract
A triple parity (TP) technique reduces overhead of computing diagonal and anti-diagonal parity for a storage array adapted to enable efficient recovery from the concurrent failure of three storage devices in the array. The diagonal parity is computed along diagonal parity sets that collectively span all data disks and a row parity disk of the array. The parity for all of the diagonal parity sets except one is stored on the diagonal parity disk. Similarly, the anti-diagonal parity is computed along anti-diagonal parity sets that collectively span all data disks and a row parity disk of the array. The parity for all of the anti-diagonal parity sets except one is stored on the anti-diagonal parity disk. The TP technique provides a uniform stripe depth and an optimal amount of parity information.
104 Citations
17 Claims
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1. A method for enabling recovery from three concurrent failures of storage devices in a storage array, comprising:
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executing, by a processor, a storage operating system of a computer; determining, by the storage operating system, that three storage devices of the storage array have concurrently failed; and in response to determining that the three storage devices have concurrently failed, executing, by the storage operating system, a triple parity recovery technique, wherein the triple parity recovery technique includes the storage operating system computing a diagonal parity block on a diagonal parity storage device of the storage array and an anti-diagonal parity block on an anti-diagonal parity storage device of the storage array that were not previously stored for the three failed storage devices. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system configured to enable recovery from three concurrent failures of storage devices in a storage array operatively connected to a computer, comprising:
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a processor configured to execute a storage operating system of the computer; the storage operating system, when executed, configured to determine that three storage devices of the storage array have concurrently failed; and the storage operating system, in response to determining that the three storage devices have concurrently failed, further configured to execute a triple parity recovery technique, wherein the triple parity recovery technique includes the storage operating system configured to compute a diagonal parity block on a diagonal parity storage device of the storage array and an anti-diagonal parity block on an anti-diagonal parity storage device of the storage array that were not previously stored for the three failed storage devices. - View Dependent Claims (15, 16)
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17. A computer-readable storage medium stored with executable program instructions for execution by a processor, comprising:
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program instructions that execute a storage operating system of a computer; program instructions that determine, for the storage operating system, that three storage devices of a storage array of the computer have concurrently failed; and program instructions that, in response to determining that the three storage devices have concurrently failed, execute a triple parity recovery technique, wherein the triple parity recovery technique includes program instructions that compute a diagonal parity block on a diagonal parity storage device of the storage array and an anti-diagonal parity block on an anti-diagonal parity storage device of the storage array that were not previously stored for the three failed storage devices.
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Specification