DiskGroup: Energy Efficient Disk Layout for RAID1 Systems

Energy consumption is becoming an increasingly important issue in storage systems, especially for high performance data centers and network servers. In this paper, we introduce a family of energy-efficient disk layouts that generalize the data mirroring of a conventional RAID 1 system. The scheme called DiskGroup distributes the workload between the primary disks and secondary disks based on the characteristics of the workload. We develop an analytic model to explore the design space and compute the estimated energy savings and performance as a function of workload characteristics. The analysis shows the potential for significant energy savings over simple RAID1 data mirroring.