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http://www.carrierhotels.com/news/2004/Apr/15/blades_present_cooling_challenges_print.html
By Rich Miller
Carrier Hotels Editor
Posted Apr 15, 2004
Blade servers have a reputation for generating more buzz than sales. Vendors have been touting the world-changing potential of blades for at least three years, but the revolution has been slow in arriving. "The fact is, today there's very little (blade deployment)," said Dominic Alcaro, director of Availability Consulting Services at APC, one of the largest vendors of data center cooling equipment.
That's starting to change, driven by enterprise companies' ambitions to consolidate their servers and data centers. And where the enterprise money goes, data center providers follow.
With the focus on blade servers shifting from "if" to "when," retooling data centers to manage higher heat loads was a hot topic at Data Center World, a conference and trade show presented by AFCOM, with numerous panels addressing the design and management issues presented by high-density computing.
The cooling dilemma is a major stumbling block. "I've got customers who won't buy a blade server because they can't cool it," said Gerry Becker, managing director of global services for Aperture Technologies, which makes data center management software. "I don't think people understand the critical nature of this issue."
In some cases, fine-tuning is all that's needed to cool high-density cabinets. For other companies, such as Evanko's client, a retrofit will do the trick.
But others will confront what Ed Koplin calls "irreversibility" - data center design problems that can't be corrected in the physical space available. "High-density configurations leave less margin of error for design errrors, misunderstandings and design flaws," said Koplin, a principal in the Baltimore design firm Jack Dale Associates, which specializes in technical facilites. The primary issue is targeting the cooling on a small area within a large data center. "The trouble with hot spots is distribution," Alcaro said. "You can make the air as cold as you like, and it doesn't matter if it doesn't get to the servers."
Many data centers are designed with "hot aisles" and "cold aisles" on either side of a bank of equipment cabinets. Chilled air from underneath the data center's raised floor is vented through tiles into the "cold aisle" and through the cabinets containing server equipment. The air emerges from the back of the cabinet into the "hot aisle" and rises to the ceiling, where it is collected and recirculated through the computer room air conditioner (CRAC) units.
That design works fine with traditional cabinets, which contain equipment using about 1.4 kilowatts of power, on average. But that changes once the load exceeds 3 kilowatts, according to Koplin.
Using air flow and fluid dynamics modeling of client facilities, Koplin found that air exiting into the hot aisle from the top of a cabinet often gets recirculated back into the cool aisle, where it re-enters the upper rows of the cabinet.
Evanko has seen the same pattern, with a center's ceiling height being the key factor. "Sixteen-foot ceiling heights allow much better cooling than an identical setup than a lower ceiling height," he said. Evanko cites ceiling height as a key differentiator between the data centers that will be able to handle high-density computing, and those that won't.
It's not just head room above the servers, either, as both raised floors and cabinets are getting higher. The enhanced cooling needs of blade installations may require raised floors as high as 36 inches (as opposed to the current standard of 18 to 24 inches), while some telecom equipment racks are not 96 inches (eight foot) rather than the traditional seven-foot height for web servers.
Which brings us back to irreversibility. "There will be throwaway data centers," said Evanko, who warned that data center managers can no longer afford to put off preparing their facilities for high-density computing.
"This is a significant problem, and will be with us for the near future," he said. "This is not going away. Blades are going to be there."
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http://www.carrierhotels.com -- Phone: (609) 243-7525
http://www.carrierhotels.com/news/2004/Apr/15/blades_present_cooling_challenges_print.html
Blades Present Cooling Challenges
By Rich Miller
Carrier Hotels Editor
Posted Apr 15, 2004
LAS VEGAS - Mark Evanko sometimes has to be the bearer of bad news about data centers. Evanko, principal engineer for facility designer Bruns Pak Inc., has a client who finished a new data center just two years ago. Now they wanted to install ultra-thin blade servers, which can be packed into cabinets by the dozens - or even the hundreds, providing more computing power per square foot of floor space.
Blade servers have a reputation for generating more buzz than sales. Vendors have been touting the world-changing potential of blades for at least three years, but the revolution has been slow in arriving. "The fact is, today there's very little (blade deployment)," said Dominic Alcaro, director of Availability Consulting Services at APC, one of the largest vendors of data center cooling equipment.
That's starting to change, driven by enterprise companies' ambitions to consolidate their servers and data centers. And where the enterprise money goes, data center providers follow.
With the focus on blade servers shifting from "if" to "when," retooling data centers to manage higher heat loads was a hot topic at Data Center World, a conference and trade show presented by AFCOM, with numerous panels addressing the design and management issues presented by high-density computing.
The cooling dilemma is a major stumbling block. "I've got customers who won't buy a blade server because they can't cool it," said Gerry Becker, managing director of global services for Aperture Technologies, which makes data center management software. "I don't think people understand the critical nature of this issue."
In some cases, fine-tuning is all that's needed to cool high-density cabinets. For other companies, such as Evanko's client, a retrofit will do the trick.
But others will confront what Ed Koplin calls "irreversibility" - data center design problems that can't be corrected in the physical space available. "High-density configurations leave less margin of error for design errrors, misunderstandings and design flaws," said Koplin, a principal in the Baltimore design firm Jack Dale Associates, which specializes in technical facilites. The primary issue is targeting the cooling on a small area within a large data center. "The trouble with hot spots is distribution," Alcaro said. "You can make the air as cold as you like, and it doesn't matter if it doesn't get to the servers."
Many data centers are designed with "hot aisles" and "cold aisles" on either side of a bank of equipment cabinets. Chilled air from underneath the data center's raised floor is vented through tiles into the "cold aisle" and through the cabinets containing server equipment. The air emerges from the back of the cabinet into the "hot aisle" and rises to the ceiling, where it is collected and recirculated through the computer room air conditioner (CRAC) units.
That design works fine with traditional cabinets, which contain equipment using about 1.4 kilowatts of power, on average. But that changes once the load exceeds 3 kilowatts, according to Koplin.
Using air flow and fluid dynamics modeling of client facilities, Koplin found that air exiting into the hot aisle from the top of a cabinet often gets recirculated back into the cool aisle, where it re-enters the upper rows of the cabinet.
Evanko has seen the same pattern, with a center's ceiling height being the key factor. "Sixteen-foot ceiling heights allow much better cooling than an identical setup than a lower ceiling height," he said. Evanko cites ceiling height as a key differentiator between the data centers that will be able to handle high-density computing, and those that won't.
It's not just head room above the servers, either, as both raised floors and cabinets are getting higher. The enhanced cooling needs of blade installations may require raised floors as high as 36 inches (as opposed to the current standard of 18 to 24 inches), while some telecom equipment racks are not 96 inches (eight foot) rather than the traditional seven-foot height for web servers.
Which brings us back to irreversibility. "There will be throwaway data centers," said Evanko, who warned that data center managers can no longer afford to put off preparing their facilities for high-density computing.
"This is a significant problem, and will be with us for the near future," he said. "This is not going away. Blades are going to be there."
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