Data centers are notorious energy hogs. And as companies like Google and Facebook have scaled up the amount of data they need to store and the number of users they need to serve, they’ve also had to figure out how to build and maintain new data centers without creating energy-sucking disasters. These two companies in particular are doing a good job--they’ve both received accolades from hard-to-please Greenpeace for their efforts.
In April, Facebook took a step towards helping other cloud leaders match its achievements by launching public dashboards for its data centers in Prineville, OR, and Forest City, NC, that keep track of power-usage effectiveness (PUE), which measures how much power a data center uses for computing versus things like cooling and water-usage effectiveness (WUE)--which measures the amount of water used for cooling versus how much power is generated. (You want both of those numbers to be as close to 1 as possible, meaning that you’re not wasting power or water.) It’s not that Facebook didn’t release these numbers before--the company just didn’t do it in real time.
"We’ve worked really hard to get the best possible performance we can to minimize energy and water consumption, and we’ve been reporting quarterly for quite some time. But looking at quarterly numbers doesn’t necessarily tell you what’s going on behind the curtain, so to speak," explains Bill Weihl, Facebook’s manager of energy efficiency and sustainability. "It’s useful to see how those [numbers] vary based on outside weather conditions."
This is all part of Facebook’s stance that "openness is our starting position unless there’s a good reason not to be," according to Weihl. But it doesn’t hurt that Facebook has strong PUE and WUE numbers. Five years ago, the typical PUE was around 2--Facebook’s generally hovers around 1.08. There isn’t much room to do better, at least with today’s technology.
On the WUE side, there simply isn’t enough data to say what’s typical in the industry. As of right now, only Facebook and eBay report their WUE numbers. "We think based on our understanding of engineering and physics that our design is pretty water-efficient, but there’s certainly room for improvement," says Weihl.
Facebook’s dashboard design is open-source (the code hasn’t yet been released), which means that other companies interested in sharing their PUE and WUE data now have a simple and attractive way to do so. As Weihl points out: "They’re very important metrics, and really paying attention to them can help in designing a system."