Patent ID: 6092215
Filing Date: 2000-07-18
Classification: G06F

Abstract:
In an array of storage devices attached to at least one host computer system, having a plurality of parity stripes, each parity stripe comprising a set of date blocks and corresponding one or more parity blocks arranged on separate storage devices such that each data block can be reconstructed using the remaining data blocks of the set of data blocks and the parity block for the stripe, and wherein when an old data block is updated with an updated data block, a corresponding old parity block is updated with an updated parity block, a method for reconstructing an unavailable data block comprising the steps of:(a) a first initiator issuing a first initiator command to each storage device to read the remaining blocks of the parity stripe;(b) coordinating on each storage device using a command queue prioritization scheme each of said first initiator commands with any update command received from a second initiator, so that the set of data blocks and the parity block are consistent; and(c) the first initiator logically combining the remaining blocks of the parity stripe read from the storage devices to produce a reconstructed data block.