Patent ID: 8171379

Claim:
A method of recovering data from disk failures, the method comprising: calculating a global parity for a group of disks comprising multiple independent Redundant Array of Independent Disks (RAID) arrays; determining if a two disk failure has occurred within a single RAID array; and if the two disk failure has occurred within the single RAID array, recovering from the two disk failure using the global parity and data from disks in the group of disks; wherein the multiple independent RAID arrays comprise two independent RAID 1 arrays and the global parity is calculated using G=g 0 D 1 +g 1 D 2 , where G is the global parity, g is equal to an integer value ‘2’, D 1 is equal to data stored on a disk in one of the two independent RAID 1 arrays, and D 2 is equal to data stored on a disk in the other of the two independent RAID 1 arrays.