METHOD AND MEANS FOR TOLERATING MULTIPLE DEPENDENT OR ARBITRARY DOUBLE DISK FAILURES IN A DISK ARRAY

摘要

Stored data can be recovered from a disk array having at least 2n + 1 physic al disks that are capable of storing n physical disks worth of data when any tw o disks fail, or when more than two dependent disks fail. Data is stored in da ta stripes that are divided into n substantially equal-sized strips and are distributed across the n disks. Each data stripe has a corresponding parity strip that is generated by including the data strips in the data stripe only once when the parity strip is generated. The data strips of each data stripe , the copy of each such data strip and the corresponding parity strip are distributed across the disks in such a manner that the data strips of each data stripe, the copy of each such data strip and the corresponding parity strip are each on a respectively different disk of the disk array.