Redundant storage array parity caching system.

摘要

An apparatus and method for improving the input/output performance of a redundant storage array system. The present invention provides a "special parity" cache within the controller for a redundant storage array system, and means for determining and caching a quantity known as the "remaining redundancy row parity" (RRR-parity) block. The RRR-parity block is equal to the old parity block of a redundancy row XOR'd with an old data block being read from the same redundancy row. By caching RRR-parity blocks, Write-intensive storage unit operations can be reduced by up to three input/output accesses.