IT power consumption is getting more attention these days. The U.S. Environmental Protection Agency's report to Congress in early August stated that the amount of energy consumed by servers and data centers, including storage, has doubled in the last five years, is expected to double again in the next five years and will cost $7.4 billion annually. So it's clear why nonprofit organizations such as The Green Grid--a consortium of IT firms promoting energy efficiency through user-centric metrics, standards development and best practices--are trying to measure data center power usage. Still, storage-specific metrics remain elusive.

"I don't know of an organization that's been formed that's storage specific," says Rick Nicholson, VP of research at Energy Insights, an IDC company, Framingham, MA. "They're all tending to focus on either ... metrics for the entire data center or they tend to be fairly server-centric."

Reps from The Green Grid claim to have storage-specific initiatives on their long-term roadmap but declined to discuss it further. Other groups working on power benchmarks include the Standard Performance Evaluation Corp. (SPEC); its first-generation SPECpower benchmark is slated for release by the end of 2007. But again, this benchmark focuses on server-class computers.

One major reason storage power metrics are so difficult to set, says Roger Tipley, senior technologist at Hewlett-Packard and a board member at The Green Grid, is that storage requires hard drives to spin continuously for performance. "I'm sure there are ways to go out and construct storage arrays that turn off all your hard drives and turn them on only when you need them," says Tipley. "But depending on your application and your service-level agreements, that may or may not play well."

The best way for storage managers to help lower data center energy consumption is by using storage products architected to reduce power usage. "The storage vendor community is ahead of the rest of the market in addressing power and cooling issues, energy efficiency-type issues," says Nicholson. For now, they'll have to do that without storage-specific metrics.

--Trina MacDonald