PowerNap: Putting Computers to Sleep

by:  Charley Wang
Institution:  University of Toronto
Date:  April 2009

We've all been told to turn off the lights when leaving the room, and now University of Michigan researchers have proposed a similar plan, called PowerNap, for the world's data centers. The results of their work have been summarized in the APLOS 2009 proceedings.

Data centers are everywhere in the world of business. Every organization has information that they need to store and access – employee information, customer information, financial information. The amount of data can be vast, running into the petabytes (a petabyte is a million megabytes). Data centers are built to store and, more importantly, to provide access to these mountains of information.

In order to be prepared for peak loads, these data centers consume vast amounts of power even when not in use. In fact, according to Thomas Wenisch, an assistant professor in the Department of Electrical and Computer Engineering at Michigan, "For the typical industrial data center, the average utilization is 20 to 30 percent." This means that a data center is only active for about 20 to 30 percent of the time – the rest is spent idling for a command.

These statistics are low considering that data centers in the United States consume as much power every year as 6 million households. That's a lot of lights to leave on!

Considering data centers in the United States consume as much power as 6 million households every year and waste approximately 70 – 80% of that energy, this presents a real problem both economically and environmentally.

PowerNap, true to its name, intends to have servers periodically nap' – turning them almost completely off for brief periods of time. This technique would save 75% of data center energy consumption every year – the equivalent of almost 5 million American households. The technology already exists and has been used extensively in the cell phone industry to extend battery life. Researchers claim that all current data servers could be relatively easily re-designed to incorporate PowerNap.

Tim Slottow, Chief Financial Officer at the University of Michigan, points out that simple data center energy initiatives already save the University close to $500,000 per year. Implementing PowerNap would be a great money- and energy-saver for any company that uses data centers.

Written By: Charley Wang

Reviewed by: Tanya Pekar, News and Features Editor Matt Getz and Professional Reviewer Lois Alexander

Published by Falishia Sloan