HoVer Erasure Codes For Disk Arrays

Abstract

We present a new family of XOR-based erasure codes primarily targeted for use in disk arrays. These codes have a unique data/parity layout, with both horizontal and vertical parity arrangements giving rise to the name HoVer codes. We give constructions that tolerate up to four disk failures. Though the codes are only approximately maximum distance separable (MDS), they have performance advantages over other codes at many common array sizes. In addition, they have fewer parameter constraints than many other codes which enable greater choices and flexibility in efficiency and performance trade-offs