Power Management in RAID Server Disk System Using Multiple Idle States

Energy efficient design for disk devices has become a very important issue, because ever increasing need for data storage systems significan tly increases the power budget in the disk array. Most research on power management in disk devices focuse s on the traditional way of stopping disk rotation. I this paper, we suggest a new approach in which the energ y consumption can be reduced without stopping the dis k rotation. The proposed Multiple Idle States (MIS) model modulates the disk RPM to optimize the energy consumption during idle periods. We present a threshold time model to calculate a minimum idle period so as to save energy without significant performance degradation. The simulation results wi th real traces show that the MIS achieves more than 58 % energy savings at low I/O workload and also gets 8% energy savings for high workload with less than 50% response time compared to the traditional shut-down power management scheme.