New datacentre survey shows mediocre results for energy efficiency

The 'average' large datacentre has a PUE of 2.9, worse than previous studies had indicated

A new survey suggests that large datacentres might be less energy efficient than was previously thought.

The survey, by Digital Realty Trust, quizzed 300 IT decision makers at large corporations in North America, each with annual revenue of at least US$1 billion or with at least 5,000 employees.

The results revealed an average PUE (Power Usage Effectiveness) score of 2.9. PUE is a measure of datacentre efficiency, and lower scores are better. Ideal scores are close to 1.0, and previous surveys have estimated the average to be closer to 2.0.

PUE is only one way of measuring energy efficiency and there's no standardized way of calculating it, so the finding isn't necessarily dire. But it's a data point suggesting that datacentres might be less efficient on average than previously thought.

The Uptime Institute, in a survey last year of 1,100 datacentre users, reported an average PUE of 1.8 to 1.89. That was an improvement over 2.5 in its 2007 survey. The U.S. Environmental Protection Agency, in 2009, reportedly put the average PUE at 1.91.

Big online firms such as Google and Microsoft have boasted of PUEs of close to 1.0, but they're special cases. Many of the datacentres they operate are new, and they invest heavily in IT efficiency, since it affects so much of their overall operating costs.

"While a PUE of 2.9 seems terribly inefficient, we view it as more being closer to the norm than the extremely low (close to 1) figures reported in the media," said Jim Smith, Digital Realty's CTO, via email. "In our view, those figures represent what a very small number of organizations can achieve based on a unique operating model."

The survey also showed that 20 percent of respondents reported having a PUE of less than 2.0, while 9 percent had a PUE of 4.0 or greater.

PUE is a ratio that looks at the total energy supplied to a datacentre, divided by the amount of energy that actually reaches the IT equipment. It reveals how much energy is expended on cooling systems and other noncompute functions. A PUE of 2.0 means that for every 2 watts supplied to the datacentre, only 1 watt reaches the computing equipment.

The average from this week's survey can be attributed to older designs and equipment, under-utilized assets, and other design and operating issues, Smith said. There are other factors, too. The figures reported "reinforce the fact that IT is not easy. Designing datacentre operations around an organization's infrastructure and operations is not a simple task," he said.

The main focus for many datacentres is making sure that services remain available, he added. That can mean installing redundant equipment, which creates inefficiency.

Despite the relatively poor PUE score, Digital Realty's survey points to increased efforts to improve efficiency. Four out of five respondents said they take steps to keep hot exhaust air from servers mixing with cold air used for cooling, known as hot-aisle or cold-aisle containment. That was up from less than two-thirds in 2011. And 85 percent use some type of datacentre infrastructure management software, an emerging class of products that can be used to improve efficiency.

Other findings include:

-- Nearly all respondents, 98 percent, said they plan to expand their datacentres in 2013 or 2014, the highest percentage in the seven years Digital Realty has sponsored the survey;

-- 65 percent would prefer to locate a new or expanded datacentre in New York City;

-- Among international locations, London (39 percent), Hong Kong (34 percent) and Tokyo (27 percent) were mentioned most often;

-- 66 percent have built or acquired a new datacentre in the past two years;

-- A quarter of respondents reported operating six or more datacentres, not including "IT closets" in branch offices;

-- The average power density is 8.5 kW per rack, and the average IT load is 2.6 mW, both up from last year.

James Niccolai covers datacentres and general technology news for IDG News Service. Follow James on Twitter at @jniccolai. James's e-mail address is james_niccolai@idg.com

Join the Good Gear Guide newsletter!

Error: Please check your email address.
Rocket to Success - Your 10 Tips for Smarter ERP System Selection

Tags hardware systemsentertainmentDigital Realty Trust

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

James Niccolai

IDG News Service
Show Comments

Most Popular Reviews

Latest Articles

Resources

PCW Evaluation Team

Matthew Stivala

HP OfficeJet 250 Mobile Printer

The HP OfficeJet 250 Mobile Printer is a great device that fits perfectly into my fast paced and mobile lifestyle. My first impression of the printer itself was how incredibly compact and sleek the device was.

Armand Abogado

HP OfficeJet 250 Mobile Printer

Wireless printing from my iPhone was also a handy feature, the whole experience was quick and seamless with no setup requirements - accessed through the default iOS printing menu options.

Azadeh Williams

HP OfficeJet Pro 8730

A smarter way to print for busy small business owners, combining speedy printing with scanning and copying, making it easier to produce high quality documents and images at a touch of a button.

Andrew Grant

HP OfficeJet Pro 8730

I've had a multifunction printer in the office going on 10 years now. It was a neat bit of kit back in the day -- print, copy, scan, fax -- when printing over WiFi felt a bit like magic. It’s seen better days though and an upgrade’s well overdue. This HP OfficeJet Pro 8730 looks like it ticks all the same boxes: print, copy, scan, and fax. (Really? Does anyone fax anything any more? I guess it's good to know the facility’s there, just in case.) Printing over WiFi is more-or- less standard these days.

Ed Dawson

HP OfficeJet Pro 8730

As a freelance writer who is always on the go, I like my technology to be both efficient and effective so I can do my job well. The HP OfficeJet Pro 8730 Inkjet Printer ticks all the boxes in terms of form factor, performance and user interface.

Michael Hargreaves

Windows 10 for Business / Dell XPS 13

I’d happily recommend this touchscreen laptop and Windows 10 as a great way to get serious work done at a desk or on the road.

Featured Content

Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?