METHOD AND SYSTEM FOR DISK FAULT TOLERANCE IN A DISK ARRAY

摘要

A two-dimensional parity method and system that provides two-disk fault tolerance in an array of disks, such as a RAID system, is presented. The method includes arranging strips containing data in the disk array into horizontal and diagonal parity sets, each parity set including at least one data strip as a member and no single data strip is repeated in any one parity set. Horizontal XOR parities are calculated for each horizontal parity set and stored in a designated disk. Diagonal XOR parities are calculated for each diagonal parity set and at least some of the diagonal XOR parities are stored in a designated disk. The remaining diagonal parities are stored in a corresponding strip in a diagonal parity stripe so that no members of a contributing diagonal parity set have the same disk index as the disk index of the corresponding strip of the diagonal parity stripe.