Patent ID: 8015472

Claim:
A method for enabling recovery from three concurrent failures of storage devices in a storage array, comprising: detecting that three storage devices in the storage array have concurrently failed, wherein the storage array is made up of a predetermined number n of storage devices, including a plurality of first devices configured to store data and row parity, one diagonal parity device configured to store diagonal parity and one anti-diagonal parity device configured to store anti-diagonal parity, wherein the predetermined number of storage devices n is p+2 and wherein p is a prime number; computing both diagonal parity and anti-diagonal parity that were not previously stored for the three failed storage devices; computing an algebraic operation on missing blocks on each of a set of failed storage devices along a row, a diagonal and an anti-diagonal; and computing a set of 4-tuple sums on a middle storage device of the three failed storage devices to enable recovery of the three concurrently failed storage devices.