Energy efficiency in the data centre is a top priority for Disney and Verizon, technology executives from the companies said last week. But the industry is still in the early stages of understanding how best to measure effectiveness.
Disney has a company-wide goal to reduce electricity consumption by 10% between 2006 and 2013, and the data center has to play a big role in achieving that objective, says Denis Weber, director of IT critical facilities infrastructure for the Walt Disney Co.
For Disney, energy efficiency is being achieved through a series of small improvements, Weber said.
"Some of it just comes down to cleaning the facility up," Weber says. "And I don't mean with a dust pail and so on and a broom, but cleaning the data centre up from obstructions and ensuring that every one of our floor tiles is sealed properly for air flow. Blanking panels--not only that we have them but that they're in the right spot. Variable speed fans and motors on our CRAC units, increasing temperature settings across the board. These are all things that are not unique to Disney. But we have done it and that's where we've started to make progress."
Disney and Verizon officials discussed their energy efficiency programs at the New York Stock Exchange last week during an event hosted by the Green Grid industry consortium.
"As much as people may look for silver bullets … it's really about all the [little] things," says Jeannie Diefenderfer, senior vice president of global engineering and planning for Verizon Services Organization. One key is finding the right temperature, and the right setting might vary across different parts of the data center, she says.
"Are you trying to make it cooler or hotter? Well it's both, right?" Diefenderfer says.
"And that's exactly what we're all doing, trying to figure out if you can tolerate the hotter temperature in any of these centres by making sure the IT computing infrastructure can tolerate it, and making certain parts of the data centre cooler so the critical infrastructure actually gets the cooling that it needs."
Still, Verizon is contemplating a more ambitious project involving solar energy. Diefenderfer says the company is trialing the use of solar for backup power sources, "with a full intent to use it if the results look positive." Verizon is also considering the use of hydrogen fuel cells, she says.
Both Verizon and Disney are measuring Power Usage Effectiveness (PUE), which compares the total power used in a facility with the power devoted specifically to IT equipment. If a PUE is 2.0, that means for every watt of power used by IT equipment an additional watt is needed to cool and distribute power to that equipment.
Disney has been able to reduce the PUE in its main data centre in Florida from 1.84 to 1.76 in the last nine months, resulting in some cost savings, Weber says.
"In our main data centre, we have a number of power monitoring capabilities both from input power and out power outbound to the loads," Weber says. "We measure it every 15 minutes, 24 hours a day, seven days a week … and report it as an updated PUE every month."
Verizon just recently started measuring PUE, and ultimately plans to measure in all of its data centres, Diefenderfer says. In general, Disney and Verizon officials say it's a good metric for tracking the efficiency of a single data centre over time, although it is less effective in comparing one company to another because of variations in how people measure.
Some companies have also found it challenging to measure PUE in mixed-use facilities in which it is difficult to decipher how much power goes to IT and how much power goes to other business functions.
Even as the industry gets used to PUE, the Green Grid is creating a broader metric that would look not just at power but at the amount of useful IT work achieved for each watt of energy used. The metric, a work-in-progress, is called DCeP, for data centre energy productivity.
Measurements of productivity are subjective, notes Mark Monroe, a Green Grid board member who is director of sustainable computing for Sun Microsystems. But the Green Grid is developing a series of proxies to quantify the usefulness of work performed by data center equipment, he said.
"Power distribution effectiveness is one thing but what do I get out of that?" Monroe notes. "Is everything going toward screen savers, or is everything doing critical business transactions? And the proxies will tell us that kind of thing. The proxies will get us most of the way there."
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