Efficient erasure recovery algorithm for double disk failure correction
Chih‐Shing Tau · Journal of the Chinese Institute of Engineers · 2008
This paper proposes an efficient parity placement scheme, Horizontal‐Oblique Parity (HOP), for protecting against double disk failures in RAID‐5 disk array systems. It keeps all data unencoded, and uses only exclusive‐or (XOR) operations to compute parity. HOP is provably near optimal in computational complexity, both during construction and reconstruction. It is optimal in the amount of redundant information stored and is sub‐optimal in its accessing. HOP works within a single stripe of blocks of sizes normally used by file systems, databases, and disk arrays.