Data Centers Get a Makeover

Computerworld - Take a stroll through almost any data center today, and you will see pretty much what you would have seen a decade ago—square white tiles over a raised floor, bright fluorescent lights, little red fire alarms everywhere and rows of faintly humming computer equipment and air conditioning gear.

But this familiar scene masks some big changes in the way that data centers are built, as well as changes in computer technology and an evolution in what data centers are expected to accomplish. Ultradense server racks, the move to distributed and virtual processing, a requirement for instant fail-over, and new requirements for IP telephony and voice over IP are all driving changes above and below the raised floor.

Keeping Cool

Perhaps the greatest challenge in data centers today is how to keep those rooms—and the components within them—cool. Facility designers used to apply a simple rule of thumb: If the room was going to be x thousand square feet, it would need y tons of air conditioning. Or designers relied on equipment "nameplates" that listed peak power usage based not on cooling requirements but on safety requirements.

Those simple approaches don't work well today. They're likely to result in expensive overcooling of the overall facility, even as temperatures in small areas—such as inside a rack of blade servers—soar.

Ron Hughes, president of California Data Center Design Group, says the typical data center last year consumed 40 watts of power per square foot and used server racks that consumed 2 kilowatts each. This year, he's designing a facility that will average 120 watts per square foot and support racks that use 4 to 5 kilowatts.

Image Credit: David Clark

"And if you look at the latest projections from HP, Sun, IBM, Dell and so on, they are predicting that racks will be 15 to 25 kilowatts for blade servers," Hughes says. "The overall direction is toward smaller footprints, increased capacity, increased power and cooling requirements. I've seen projections for blade servers as high as 30 kilowatts per rack, and that's well over 500 watts per square foot."

The issue at those levels isn't cooling per se, but affordable cooling. Hughes says that at 40 watts per square foot, it costs $400 per square foot to build a data center, or $20 million for a 50,000-square-foot facility. But at 500 watts per square foot—which Hughes says we could see by 2009, well within the lifetime of any data center built today—the amount of air conditioning, uninterruptible power supply (UPS) units, power generators and related gear jumps dramatically. Construction costs soar to $5,000 per square foot, and the same data center busts the budget at $250 million, he says.