Edgy About Blades

Computerworld - What's not to like about blade servers? The technology is sleek and sexy. With fewer cables to interconnect, blades, which share a common backplane, are easier to manage than other types of servers. They take up less floor space, and vendors are advertising them heavily as an alternative to stand-alone and rack-mounted servers. Yet even as analysts predict growth, some IT organizations are hesitant about authorizing broad deployments. IT professionals cite concerns about heating and power, vendors' proprietary designs, the relative immaturity of the technology and premium prices.

While market research firm IDC predicts strong growth for blades over the next few years, Gartner Inc. projects more modest gains, citing user concerns. "By 2009, only approximately 16% of servers installed worldwide will be in the blade format," says Gartner analyst Jane Wright.

Cooling and power top the list of concerns for Capgemini clients, says John Parkinson, chief technologist at the Chicago-based IT consultancy. He says that in some cases dense blade deployments have required "major upgrades to power... and air handling."

Dealing with power and cooling issues can add significantly to the total cost of ownership, says Umesh Jagannatha, senior manager of technical services at Embarcadero Systems Corp. in Alameda, Calif. Embarcadero uses blades for a port security application but has passed on other uses for now.

Derek Larke is currently testing an IBM BladeCenter but has all but decided to go with 1U (1.75 in. tall) servers. "This thing is cranking out heat like there's no tomorrow. We noticed that the server room temperature has gone up," says Larke, manager of information services at Fun Sun Vacations Ltd. in Edmonton, Alberta.

Tim Dougherty, director of eServer BladeCenter marketing at IBM, says the problem isn't blade-specific but reflects an overall trend toward increasing processor density in data centers. IBM's BladeCenter design won't overheat, he says. But blade-filled server racks can create hot spots in the data center that air conditioning units can't handle, so administrators commonly leave racks partially empty in an effort to distribute the heat more evenly.

Image Credit: Wendy Wahman

Robert Kreitzer, vice president of the Intel server engineering team at KeyCorp in Cleveland, says he watched IBM representatives demonstrate how they could cool a fully loaded BladeCenter rack, but the real-world advice he received was different. "I asked them full on, 'You don't really recommend filling the rack, do you?'" says Kreitzer, recalling that the representatives acknowledged that they didn't recommend it.

Wright says she regularly fielded calls about overheated blade racks a year ago. That problem has disappeared because vendors no longer fill racks with blades, she says. IBM counters that many of its customers do, in fact, operate with fully loaded racks.