Dual Crosshatch Disk Array: a Highly Reliable Disk Array System 1

In this paper, we propose a highly reliable disk array architecture called Dual-Crosshatch Disk Array (DCDA). We have proposed a low overhead, triple-erasure correcting parity organization called interleaved 2d-parity scheme. This parity scheme is used as the basis for the design of the DCDA architecture. DCDA uses a hybrid approach of RAID-4 and RAID-5 with one dedicated parity group and another parity group with block-interleaved data and parity. This architecture has very high reliability with low overheads, good degraded-mode performance, and acceptable normal-mode performance. The results obtained from simulations indicate that DCDA is about 10 4 times more reliable than the best existing disk array architecture for the parameters considered in this paper. The average response time and throughput of DCDA is better than that of the RAID-5 organization.