Four ways to save energy - and $$$ - in legacy data centers

Will a server consolidation project that cuts total servers by 50% through virtualization cut operating costs by that much? Not even close. That's just one of the data center energy efficiency tips that hit the cutting room floor as my feature story, Data center density hits the wall, launched this week.

Here are four more to consider:

Consolidation through virtualization: A 15% solution.

Consolidating servers using virtualization reduces the total number of physical servers and saves energy, but not by as much as you might think. Why? One reason is that the more fully configured replacement servers tend to use more energy than those they replace. So what should you expect to see in energy savings from a server consolidation project? Ben Stewart, vice president of engineering at hosted service provider Terremark, sees a lot of them at the company's colocation data centers. On average, he says, "You get about a 15% power savings by doing the reduction in space."

High density servers? Spread 'em, Danno.

Going to a higher server density may get you better performance per square foot, but it doesn't always pay off when you look at the big picture.

In the grand scheme of things, higher energy density cabinets are not always the best solution in your data center when overall redundancy, power distribution, cooling and floor space considerations are taken into account. Do so and you may run out of power and cooling capacity, leaving stranded floor space -- also called "white space." Increasing density also creates extra expense for supporting equipment that you don't have when you spread out.

So, rather than invest in expensive cooling system upgrades to support those increased densities, stay within the design specification of your data center and go to a larger footprint to distribute the power and cooling load, says Peter Gross, vice president and general manager at HP Critical Facilities Services. "The money is not in square footage. It's in the power and redundancy costs."

When it comes to cooling costs, there is such a thing as a free lunch.

A new data center that's well designed and located in the right geographic region, such as the Pacific Northwest or Canada, can dramatically reduce or eliminate cooling costs part of the year. These data centers have installed economizers that use cool outside air instead of chillers to keep the data center cool.

These aptly named "free cooling" technologies deliver cool outside air to the data center through an air-to-air or air-to-water heat exchanger system. Free cooling isn't just about being green: The operating budget savings can be substantial. Wells Fargo installed a free cooling system three years ago that saves its Minneapolis data center $450,000 a year in electricity costs.

Excuse me, but do you need professional help?

Don't be afraid to ask for it. If you're running an older data center and don't know where to begin -- or even if you think you do -- hiring a consulting engineer could pay off.

A typical engagement doesn't have to be a big affair, with a professional engineer conducting a full blown computational fluid dynamics analysis of your entire data center. By applying best practices, a good consultant can cut energy consumption by one third to one half more in an older data center.

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