Patent ID: 7392458

Claim:
A method for performing parity checking in a RAID-6 environment in which a plurality of bytes over a plurality of disks are checked to ensure parity data is in sync, each such byte associated with a first parity value and a second parity value, the method comprising the steps of: performing parity checking to determine whether parity data is in sync; during the step of performing parity checking, identifying each byte for which a first parity equation is not satisfied; for each identified byte, calculating a first error value using the first parity equation; for each identified byte, calculating a second error value using a second parity equation; and based on the first error value and the second error value for each identified byte, identifying a faulty disk drive in the RAID-6 environment, wherein the step of identifying includes the steps of: for each of the plurality of bytes, determining as a first condition if the first error value and the second error value are either both non-zero or both zero; for each of the identified bytes, determining as a second condition if the first and second error values indicate a valid disk index within the RAID-6 environment; and for each of the identified bytes, determining as a third condition if the valid disk index is the same for all such bytes.