Disk power-management is on Microsoft's green agenda

Microsoft has been turning up the volume on its green initiatives across the company, as of late. I recently stumbled onto yet another one: DiskEnergy.

DiskEnergy is a Microsoft Research project headquartered at the company's Cambridge, U.K. research facility. So far, there's very little public information about it. But here's a description of what's in the works, courtesy of the Microsoft Research site:

"Power consumption is a major problem for data centers of all sizes which impacts the density of servers and the total cost of ownership. This is causing changes in data center configuration and management. Some components already support some power management features, for example server CPUs support dynamic clock and voltage scaling that enables power requirements to be reduced significantly during idle periods. Storage subsystems do not have power management and are consume a significant amount of power in the data center. Modern enterprise grade disks require approximately 10W when idle. As storage requirements generally increase in data centers, the number of disks in data centers is increasing proportionally."

The DiskEnergy researchers just published a white paper, entitled "Write Off-Loading: Practical Power Management for Enterprise Storage."  The team is planning to present its paper at the Usenix FAST conference in February 2008.

The synopsis:

"Based on 1-week long traces of core servers in our data center, we have found that there are significant periods of idle time during which disks can be spun down, and even longer 'write-only' periods during which all I/O operations are writes. Based on this we have developed a technique called “write off-loading” which allows disks to stay spun down during these write-only periods, by temporarily off-loading the write requests to other volumes in the data center. Our results show that this provides power savings of 45—60%."

According to the paper's conclusion, the DiskEnergy researchers are working on new tools "to help administrators decide how to save the most energy with the least performance impact. "

Various teams at Microsoft have been looking into improving power-consumption of PCs and servers. Last year, the company announced an RFP of $500,000 for sustainable computing and and "adaptive power management solutions for maximizing the energy efficiency of computing infrastructure."