Researchers from Microsoft have been examining ways to save energy in basic data center processes, and are presenting a paper at Usenix (link via Mary Jo Foley) outlining some of their findings. The paper discusses an energy-saving technique called write off-loading, which alters the input/output pattern in storage systems to generate idle periods during which disks can be spun down save energy. Here's a summary:
Our analysis shows that simply spinning disks down when idle saves significant energy. Further, write off-loading enables potentially much larger savings by creating longer idle periods. To validate the analysis we implemented write off-loading and measured its performance on a hardware testbed. The evaluation confirms the analysis results: just spinning disks down when idle reduces their energy consumption by 28
