A cascading Latin scheme to tolerate double disk failures in raid architectures

Abstract

In recent years, a lot of XOR-based coding schemes have been developed to tolerate double disk failures in Redundant Array of Independent Disks (RAID) architectures, such as EVENODD-code, X-code, B-code and BG-HEDP. Despite those researches, the decades-old strategy of Reed-Solomon (RS) code remains the only popular space-optimal Maximum Distance Separable (MDS) code for all but the smallest storage systems. The reason is that all those XOR-based schemes are too difficult to be implemented, it mainly because the coding-circle of those codes vary with the number of disks. By contrast, the coding-circle of RS code is a constant. In order to solve this problem, we develop a new MDS code named Latin code and a cascading scheme based on Latin code. The cascading Latin scheme is a nearly MDS code (with only one or two more parity disks compared with the MDS ones). Nevertheless, it keeps the coding-circle of the basic Latin code (i.e. a constant) and the low encoding/ decoding complexity similar to other parity array codes.