Data center managers are packing more computing power into smaller footprints. But today's racks and blades produce...
massive amounts of heat per square foot in comparison with those old tower servers. Left unchecked, this heat can cause an IT meltdown.
So is the answer to the escalating heat problem in the data center better designed servers or better designed rooms? Are IT shops favoring one approach over the other? And as you plan your next server refresh, what should you be looking for?
Time for hardware innovation
Advances in server technology may give data center managers a little room to breathe. Innovations from chip technology to server construction are improving hardware's capability to deal with high-density environments.
According to Gordon Haff, analyst with Nashua, N.H.-based Illuminata, the days of using traditional server cooling methods are over. Companies
going forward with dense server environments will need to use every little piece to get closer to its goals. Upshot: A cooler server starts with the processor.Water is going to come back into the data center. The only question is when, and for what purpose.
Robert E. McFarlane
presidentInterport Financial Division, Shen, Milsom & Wilke Inc.
Multi-core processing is one technology with the potential to reduce data center cooling requirements. In principle, multi-core processors could operate at a lower frequency, using less power to achieve today's computing levels, thereby running cooler.
Dual-core technology has been around since the 1990s, but AMD Inc., in Sunnyvale, Calif. and Intel Corp., in Santa Clara, Calif., have pushed it into the x86 market recently. The Intel offering is scheduled to be available early in 2006, while the beta versions of the AMD product have been shipping since January 2005.
Haff predicts that further out, as multi-core processing develops, the possibility of operating at lower frequency levels is more likely, but current dual-core chips will not inspire people to lower usage levels.
"We've learned to live with where we are regarding server heat issues," Haff said. "People are going to run dual core processors at the peak power levels to get increased performance, rather than running them at half power to get the power of today's CPUs."
Another new chip technology designed to help servers run cool is demand-based switching. Intel's 64-bit Xeon chips use this feature which allows systems to be throttled down when not in use. According to server vendors, the technology has the capability to save customers 24% annually in power costs.
A step up from chips, the server design also plays a role in heat issues. IBM is a leader in cooling innovation, though many of its cooling features aren't new, since they often trickle down from the mainframe.
Fewer parts, cooler server
Calibrated vectored cooling (CVC) is an example. CVC optimizes the path of cooled air flow through the system, allowing servers to use fewer fans and less power. It directly channels refrigerated air through the hottest parts of the server. IBM recently offered CVC for its xSeries and blades. CVC technology for blades had allowed IBM to launch the first Xeon-based blade product.
Where blades are concerned, it's not just IBM stepping up to the plate with cooling strategies. Almost every blade manufacturer has been forced to deal with cooling issues, including Marlboro-Mass.-based Egenera.
Egenera was founded in 2000 by Vern Brownell, former chief technology officer of Goldman Sachs. The company has focused solely on blade manufacturing and has become a major player in that market in a very short time.
According to Susan Davis, Egenera vice president of marketing and product management, data center managers don't always have the luxuryof designing a state of the art server room. Since so many data centers are limited to working with available resources, Davis feels better server design can have a broader impact.
Egenera blades are all processor and memory. There are no disk drives, connector slots or NIC cards to block airflow. None of the extraneous hardware is included in the actual server. According to Egenera, eliminating as many components as possible allows direct flow to critical areas.
When data center design is key
Despite vendors' efforts to help alleviate the data center heat wave, some experts predict specialized cooling and room engineering will be necessary to meet computing demand.
"We are very close to the limit of how much more energy-efficient we can make CMOS [complementary metal-oxide semiconductor -- used in the transistors of most microchips] technology, and there is nothing anyone sees on the horizon in the way of a technical breakthrough to replace it with much more energy-efficient devices," said Robert E. McFarlane, president of the Interport Financial Division of New York-based Shen, Milsom & Wilke Inc. "Therefore, as compute power goes up and is crammed into smaller and smaller spaces, the stuff is simply going to get hotter."
Cool waters run deep
So what is the engineering solution people are talking about? According to Charles King, principal analyst with Hayward Calif.-based Pund-IT research, it's nothing new. In fact, the idea was cutting edge thirty years ago.
Some experts have proposed moving towards liquid cooling, much like the old Cray systems -- the liquid cooled supercomputers from the 1970s.
"Water is going to come back into the data center. The only question is when, and for what purpose," said McFarlane said. "Roger Schmidt, chief thermodynamics engineer at IBM, [recently] admitted that, while everyone knows servers are one day going to be water-cooled, no one wants to be first, believing that if their competitors still claim they are fine with air cooling, the guy who goes to water cooling will rapidly drop back in sales until others admit it is necessary."
King agrees. "Vendors are going to do everything they can to avoid going to liquid cooled systems. It makes everything more complex."
Cold air, warm parts
But conventional under-floor air can effectively cool hardware only to a certain point.
"Even if data center managers could get enough cold air under the floor to equipment locations, getting it evenly up the heights of cabinets is another problem," said McFarlane said. "And dealing with the problem of keeping return air from mixing with the cold air is even more difficult, both to predict and to accomplish."
Therefore, while it is important to design new data centers with every possible technique for maximizing conventional performance, McFarlane predicts much of what is coming or already here is going to require localized cooling techniques.
These options include specialized enclosures, such as West Kingston, R.I.-based APC promotes with their InfraStruXure line. These systems include power, cooling, and environmental management within a rack. According to APC, this can even eliminate the need for raised floors in many applications.
Other options include overhead spot cooling or liquid-cooled cabinets such as what the Columbus, Ohio-based Liebert Corp.offers. The Liebert X-treme Density heat removal system for example uses overhead fans and a waterless refrigerant pump to maintain safe rack temperatures.
In the battle against IT's warming trend, the value and limitations of each vendor and approach need to be weighed. According to Charles King, IT professionals can be much more proactive in data center design than they can on the manufacturing end.
Other experts may disagree, arguing that cooler servers are vital for customers to keep buying new generation servers and making them co-exist within shrinking confines.
But either way, these approaches aren't mutually exclusive. And data center managers would be wise to employ every advantage possible to protect hardware from a meltdown.