PMSH: a new algorithm for RAID data migration based on stripe unit heat

Traditional RAID has the characteristics that location of stripe unit in each disk is stochastic and static, and that the outer zone of the disk has higher data transfer rate as compared to the inner one. Facing this situation, to exploit RAID I/O performance fully, this paper proposes a new algorithm PMSH (placement and migration based on stripe unit heat) for RAID stripe unit data to be placed optically and migrate dynamically. Based on the heat of RAID stripe unit, PMSH keeps migrating the frequently accessed stripe unit to the disk zone with higher data transfer rate, thus optimize the location of data in RAID disks, and make the data distribution adapt to the evolution of file access pattern dynamically as well. Simulation results demonstrate significant RAID I/O performance improvement using PMSH.