Failure Evaluation of Disk Array Organizations

In this paper, we present an evaluation of some of the disk array organizations proposed in the literature. We evaluate three alternatives for sparing, hot sparing, distributed sparing and parity sparing, and two options for data layout , regular RAID5 and block designs, and systems based on combinations of these data layout and sparing alternatives. We evaluate the performance of these organizations in various modes of operation, with diierent reconstruction strategies. It is shown that parity sparing and distributed sparing have improved performance and shorter reconstruction times over hot sparing. It is shown that both block designs as a data layout policy and distributed sparing as a sparing policy reduce the reconstruction time after a failure. We also study the impact of reconstruction strategies and show that at higher workloads, choice of reconstruction strategy has a signiicant impact on the performance of the systems.