Greening Your Data Center � You May Have No Choice

By Paul Rubens (Send Email)
Posted Aug 22, 2007


The writing has been on the wall for some time. Limited IT budgets and skyrocketing electricity costs combined with the possibility of more government intervention may force enterprises to create environmentally friendly data centers.

Electricity use in data centers is skyrocketing, sending corporate energy bills through the roof, creating environmental concerns and generating negative publicity for large corporations.

Because IT budgets are limited and because governments in Europe and the United States may soon impose carbon taxes on wasteful data centers, something's got to give. Data centers are going to have to "go green."

“There's no doubt that in the short term this problem is a financial one, but behind that there is the need of organizations to be seen to be green.”

—Rakesh Kumar, Gartner.

It's not as if no one saw this coming. The aggregate electricity use for servers actually doubled between 2000 and 2005, both in the U.S. and around the world as a whole, according to research conducted by Jonathan Koomey, a consulting professor at Stanford University.

In the U.S. alone, servers in data centers accounted for 0.6 percent of total electricity usage in 2005. But that's only half the story. When you include the energy needed to get rid of the heat generated by these servers that figure doubles, so these data centers are responsible for about 1.2 percent of total U.S. electricity consumption, equivalent to the output of about five 1000MW power stations, and costing $2.7 billion — about the gross national product of an entire country like Zambia or Nepal.

Unless data centers go green, costs energy costs could soon spiral out of control, according to Rakesh Kumar, a vice president at Gartner. In a report titled "Why 'Going Green' Will Become Essential for Data Centers" he says that because space is limited, many organizations are deploying high-density systems that require considerably more power and cooling than last generation hardware.

Add to that the rising global energy prices, and the proportion of IT budgets spent on energy could easily rise from 5 percent to 15 percent in five years. The mooted introduction of carbon taxes would make this proportion even higher. "When people look at the amount of energy being consumed and model energy prices, and think about risk management and energy supply, they should begin to get worried," Kumar said.

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It's Not Easy Being Green
Since most data centers historically have not been designed with the environment in mind, Kumar says more than 60 percent of the energy used for cooling purposes is actually wasted. This is bad for the environment and reflects poorly on the organizations concerned — especially if, as increasingly is the case, they have corporate social responsibility commitments. And as a growing number of companies are adopting a "carbon neutral" policy (either out of genuine concern for the environment of for the positive PR this can produce) pressure from head office to reduce the carbon footprint of the data center, to help reduce overall carbon emissions, will become more intense. "There's no doubt that in the short term this problem is a financial one, but behind that there is the need of organizations to be seen to be green," he said.

So what can be done to "green" the data center? "There is no one solution that will solve the problem — this is a collective issue and it will require a raft of solutions," Kumar said. "You need to start by getting some metrics to understand the problem, because it's not going to go away," he said.

What's That Term?
Not sure what a particular term means? Check out the searchable ServerWatch Glossary.

The ideal solution is to start from the ground up by designing and building a new data center with energy efficiency in mind. This includes looking at the thermal properties of the building being constructed, the layout of the building for maximum cooling efficiency, and even the site of the building: Locating a new data center far from urban areas means that it might be more feasible to incorporate renewable energy sources such as wind turbines or solar panels into the design, for example. For more specific guidance, organizations can turn to standards such as the U.S. Green Building Council's Leadership in Energy and Environmental Design certification. Vendor programs such as the Green Grid, an information network sponsored by AMD, IBM, HP and Sun, may also be a useful source of information.

Assuming you're not quite ready to tear down your buildings and start again, there's still plenty you can do to reduce your electricity bill and reduce your carbon footprint. Perhaps the most effective action you can take is to reduce the number of servers in use at any one time. Each server you switch off can reduce your electricity bill by up to $500 per year (and reduce the amount of carbon dioxide released into the air annually by perhaps 2000 pounds) directly, with about the same savings again realizable from reduced cooling requirements.

It may be that you have servers that don't need to be on at all hours of the day and night, but it's more likely that you can reduce the number of severs you need through virtualization. If you run corporate applications on separate servers, many may be only 10-20 percent utilized. Virtualization can dramatically cut the number of physical servers you need, while technology from companies such as VMWare can ensure that your virtual machines can be switched to higher-capacity physical machines during peak times.

If you do retire some servers, it obviously makes sense to get rid of the older ones. This has the added benefit of increasing your overall server energy efficiency because newer multi-core chips can offer significant performance gains over older ones, whilst using almost 50 percent less power. Power management technologies such as Intel's Demand Based Switching can further reduce individual processor electricity consumption by up to 30 percent.

Another area where you can make significant power savings is server power supplies themselves. That's because they can vary enormously in efficiency, especially under certain loads. Bad power supplies waste about half of the energy they consume (and thus the same again used by cooling systems to dissipate the heat generated by this wasted energy.) To compound this, power supplies running at a small fraction of their rated capacity are often even more inefficient. Look for power supplies with the 80 Plus certification — this means that the power supply will run at at least 80 per cent efficiency even when running at just 20 percent of its full capacity.

It's a Long Way to Tipperary
The answer to the question "how do you make your data center greener" is similar to the traditional question from the Emerald Isle: "How do you get to Tipperary?" The answer in both cases is "If I were you I wouldn't start from here." What this means is that while you can certainly make savings by switching power supplies and switching off unused machines, the real solution requires a total rethinking of the data center. This ranges from the design of the buildings and cooling systems they contain, to the extensive use of virtualization to increase server utilization, all the way down to the use of energy efficient equipment, from power supplies to smart, power-managed processors. It's not a cheap undertaking, but one that may prove vital for the survival of the data center, the corporation, and perhaps — in a small way — even the planet.

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