Failure evaluation of disk array organizations

The authors present an evaluation of some of the disk array organizations proposed in the literature. They 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. The performance of these organizations is evaluated with different reconstruction strategies. It is shown that parity sparing and distributed sparing have better performance and shorter reconstruction times than 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. The impact of reconstruction strategies is studied, and it is shown that, at higher workloads, choice of reconstruction strategy has a significant impact on the performance of the systems