Networked Enterprise Featured Article

So much of today’s computing world is tied to data centers, thanks to the prominence of cloud computing, hosted services, mobility and a variety of other technology trends and services. And data center operators are being charged with implementing efficiency standards on a granular level. One of the most important components when it comes to efficiency, conservation and cost savings is power consumption, and it is becoming an increasingly powerful factor in the operating architecture of any data center.

Perhaps the most popular industry standard used to govern power conservation is the power usage effectiveness (PUE) benchmark. Developed by The Green Grid (News - Alert) Association in 2007 to measure data center infrastructure efficiency, the PUE is the general measurement of how efficiently a data center uses energy. It represents the ratio of the total amount of energy used by a data center facility to the energy delivered to computing equipment, and that magic number should ideally be 1.

The PUE is not absolute, however, for a number of reasons. Primarily, the exact items included in the measurement can vary from company to company and when combined with other variables, this can skew the numbers considerably. For example, the climate in the regions where data center facilities are located is not taken into consideration. So a data center in a warmer climate will require significantly more cooling than one located in Alaska. And since cooling systems account for around 30 percent of energy consumption, they may drive up the PUE – even if the data center is operating more efficiently overall than a facility in a cooler climate.

Additional factors that can incorrectly skew the PUE include exactly which devices within the data centers should be included in calculations along with data center subsystems like outdoor lighting, which may not apply to all facilities. Mixed-use facilities that share resources and subsystems with non-data center functions also complicate PUE calculations, as well as loads that are intrinsically tied to power measurement points but that are not related to data center usage.

So the PUE is open to interpretation, and the final ratio will depend on how the data center operator is measuring their own infrastructure. Take Google (News - Alert), for example, one of the largest data center operators on the planet. According to their data center performance reports, “We could report much lower numbers if we took the loosest interpretation of the Green Grid's PUE measurement standards. In fact, our best site could boast a PUE of less than 1.06 if we used an interpretation commonly used in the industry. However, we're sticking to a higher standard because we believe it's better to measure and optimize everything on our site, not just part of it. Therefore, we report a comprehensive trailing twelve-month (TTM) PUE of 1.12 across all our data centers, in all seasons, including all sources of overhead.”

Vendors in the data center power industry are working to better define the PUE benchmark in a standardized way. Panduit, a company specializing in power efficiency and DCIM solutions, offers its SmartZone solutions to help lower PUEs holistically. The offering works to gather granular information about energy consumption at UPS, PDU and IT equipment inputs. It divides facilities into six logical zones with different levels of granularity and relevance to gain a better understanding of infrastructure energy usage.

The Green Grid is working on PUE 2 Category 3, the most rigorous measurement of power usage to date. As the standard becomes more stringent and refined, data center operators are going to need to implement smarter power management solutions to ensure they are staying on top of all aspects of their energy usage and consumption.