RAID SYSTEMS AND METHODS FOR IMPROVED DATA RECOVERY PERFORMANCE

A RAID system, RAID controller, method, and computer program product for reducing the number of reads of XOR data in a multi-storage-enclosure RAID array includes a RAID array controller that implements a selected distributed RAID scheme. The RAID array controller determines a set of drives and logical block addresses corresponding to a parity group and divides the set of drives into subsets of drives that are located within each individual storage enclosure of the multiple storage enclosures. The controller issues a single EnclosureXOR Read to each storage enclosure corresponding to the subsets of drives to read enclosure-level intermediate XOR data calculated by each storage enclosure for each subset of drives and in response to receiving the enclosure-level intermediate XOR data results from all storage drives in the parity group, and calculates an array level XOR result by XORing the enclosure-level intermediate XOR data results from the storage enclosures.