Blades raise heat, power issues

As blade servers become more powerful, business customers need to think carefully about how to cool the thin devices, which can generate more heat and consume more power in small spaces than most data center managers are used to.

At the recent Server Blade Summit in San Jose, attendees saw firsthand how the increase in power demands from the densely packed systems could affect enterprise data centers: An interoperability demonstration of working blade systems caused the power in the Wyndham Hotel that hosted the conference to flicker on and off sporadically throughout the event.

While analysts and industry observers note that the Wyndham wasn't designed as a data center, they agree that power and heat issues will be a key concern as businesses re-architect their data centers to make more efficient use of their compute resources. System density is increasing throughout the industry as chip manufacturers continue to boost the speed and power of CPUs, analysts say.

"Heat and power management are issues for the whole industry, not just blades," says Mark Melenovsky, research director of global enterprise server solutions at IDC. "But blades do kind of concentrate the concern because of the small form factor."

A senior vice president of critical systems at a large financial institution who asked not to be named says his company is experiencing "surprising increases in power density" as it brings in partitioned servers, and storage-area networks, and looks at deploying blade servers.

"With blades and other high-density servers, we saw in the same server footprint power density could increase six- to eightfold," he says. "Where we saw something like 3 kilowatts of power with a standard server cabinet, partitioned servers could use 24 kilowatts of power, and blades are the same or worse."

Blades were developed in 2000 to meet the needs of rapidly expanding Internet data centers. Blade pioneers such as RLX Technologies offered service providers increased server density and avoided dramatic increases in power consumption by using lower-power processors.

However, as the service provider market slowed and blade server vendors turned to enterprise customers, they found that the lack of computing power limited blade adoption. Today, blades are becoming increasingly powerful. By 2005, blades should be able to run 80% of enterprise applications, Gartner says in a research note it published late last year that focused on server density.

At the same time, power and heat issues are taking center stage.

"Enterprises must . . . carefully factor in the power and cooling demands of these blades," the Gartner report says. "Many enterprises will not be able to achieve optimal density because of environmental limitations. Simply put, the vision of hundreds of blade servers in a rack is unrealistic for most enterprises in the next five years."

IDC's Melenovsky says that he doubts the issues of heat and power will stem the adoption of blade servers in the long term. About 185,000 blade servers were sold last year, which accounts for just 2% of the overall server market, according to IDC. IDC expects blade server sales to jump to more than 450,000, or about 8% of the market, this year.