A Light-weight Approach to Reducing Energy Management Delays in Disks

Today’s enterprise computing systems routinely employ a large number of computers for tasks ranging from supporting daily business operations to mission-critical backend applications. These computers consume a lot of energy whose monetary cost accounts for a significant portion of an enterprise’s operating budget. Consequently, enterprises employ energy saving techniques such as turning machines off overnight and dynamic energy management during the business hours. Unfortunately, dynamic energy management, especially that for disks, introduces delays when an accessed disk is in a low power state and needs to be brought into an active state. Existing techniques mainly focus on reducing energy consumption and do not take advantage of enterprisewide resources to mitigate the associated delays. Thus, systems designers are faced with a critical trade-off: saving energ