The approximate parameters analysis of mS/spl I.bar/RAID

In order to overcome the problem of making choice configuration parameters of RAID, we bring out mS_RAID. A key problem for it is how to choose the optimal stripe unit size. However, till now this issue is not solved, especially under synchronous workload, because of the complexity about read-write of RAID and closed fork-join queue network. In this paper, we first present a read-write model of disk array under little and large I/O requests based on closed fork-join queue network model and analyze read-write action in RAID, and then deduce a approximately analytical expression to predict disk array´s the mean response time under variety workload parameters designed to emulate real world condition. According to the analytical expression, we can get optimal stripe unit size under minimum mean response time. Finally, a large number of simulations have been carried out to validate our analytical result.