Datacenterknowledge reports on Yahoo’s disclosure of its 1.21 PUE at O’Reilly’s Velocity 2009.

Yahoo Unstealths Its Data Center Efficiency
June 24th, 2009 : Rich Miller

The Yahoo data center in Quincy, Washington includes cooling-optimized "podules" with a PUE of 1.21 (Photo: Yahoo Inc.)

When it comes to data center efficiency, Yahoo has maintained a lower profile than rivals Google and Microsoft. But the Yahoo team is building a compelling data center story of its own, with innovations in cooling design and energy efficiency ratings approaching the best that Google has achieved.

Yahoo’s Adam Bechtel began telling the story yesterday at the O’Reilly Velocity 2009 conference in San Jose, Calif. Bechtel, the chief architect of Yahoo’s data center operations, shared details of a patented cold-aisle containment system that integrates an overhead cooling module, building the air conditioning units into the top of a “podule” of cabinets packed with servers.

That design has helped Yahoo lower its Power Usage Effectiveness (PUE) to 1.21, according to Bechtel, just a hair shy of the best numbers disclosed by Google and a slightly better than the lowest PUE reported by Microsoft. The PUE metric (PDF) compares a facility’s total power usage to the amount of power used by the IT equipment, revealing how much is lost in distribution and conversion.

What is missing is under what conditions was 1.21 determined.

What is needed is transparency for PUE claims. Wouldn’t it be great if you could connect to a web service at google, microsoft, and yahoo data centers to get their PUE at any time of the day with the current weather conditions? And, make a request for any other time for the PUE number?

Once we see a data center do this, I’ll believe the PUE claims would stand up to a compliance audit.

I am waiting for a claim of 1.10 PUE. Competition is good, and this all helps educate more people. But, we need more transparency on how PUE is calculated.