Improvements in disk speeds have not kept up with improvements in processor and memory speeds. One way to correct the resulting speed mismatch is to stripe data across many disks. In this paper, we address how to stripe data to get maximum performance from the disks. Specifically, we examine how to choose the striping unit, i.e. the amount of logically contiguous data on each disk. We synthesize rules for determining the best striping unit for a given range of workloads. We show how the choice of striping unit depends on only two parameters: 1) the number of outstanding requests in the disk system at any given time, and 2) the average positioning time
Peter M. Chen, David A. Patterson