Write Off-Loading: Practical Power Management for Enterprise Storage

In enterprise data centers power usage is a problem impacting server density and the total cost of ownership. Storage uses a significant fraction of the power budget and there are no widely deployed power-saving solutions for enterprise storage systems. The traditional view is that enterprise workloads make spinning disks down ineffective because idle periods are too short. We analyzed block-level traces from 36 volumes in an enterprise data center for one week and concluded that significant idle periods exist, and that they can be further increased by modifying the read/write patterns using write off-loading. Write off-loading allows write requests on spun-down disks to be temporarily redirected to persistent storage elsewhere in the data center. The key challenge is doing this transparently and efficiently at the block level, without sacrificing consistency or failure resilience. We describe our write offloading design and implementation that achieves these goals. We evaluate it by ...

• Type: Conference
• Year: 2008
• Where: FAST
• Authors: Dushyanth Narayanan, Austin Donnelly, Antony I. T. Rowstron
• Keywords: Enterprise Data Center, FAST 2008, Idle Periods, Operating System, Significant Idle Periods