Cool Servers Are A Hot Issue

In electronics-laden environments, heat is a constant enemy, and the battlefront exists wherever servers are found. Users and server manufacturers are sharing an arsenal of weapons designed to beat the heat"especially in servers using today's new, more powerful processors. In fact, the war can be won only if both the equipment and its environment are optimized to keep things cool.

"Heat is always an issue, and, in certain environments, it becomes the biggest issue to overcome," said Tim Dougherty, director IBM eServer Products at IBM Corp., Somers, N.Y. "The classic example today is with blade servers, because you have more things in a smaller space. Also, in data centers, as faster machines came along, much of the floor space was being taken up by cooling facilities."

In data centers, especially those located in urban areas, there is constant pressure to balance the plant's physical confines with the increasing need for cooling. As processing power within servers rises, and blade servers allow for more power per square foot, heat becomes a growing issue.

"The advent of [the newest] servers has created loads in excess of 10,000 watts on a cabinet-by-cabinet basis. In most data centers in operation today, they expected loads from 5,000 to 7,000 watts, max," said Ken Baker, data center infrastructure technologist, Hewlett Packard Co.'s Industry Standard Servers, Palo Alto, Calif.

Server manufacturers are optimizing their designs for heat dissipation. IBM, for example, uses calibrated vector cooling, which specifies that a certain amount of air must be present between the blades. One set of fans pulls air through the chassis and cools all the blades and modules within the unit.Other server makers put a fan on every blade, which increases cooling power, but also generates more heat. In addition to looking at airflow through a server rack, manufacturers also are examining heat sink technology, and are considering replacing air with water or chemical cooling, said Frank Schwartz, senior staff member of the office of the CTO, Volume System Products, at Sun Microsystems, Menlo Park, Calif.

Evolution of server technology is not enough. Often, users fail to readjust their cooling and design as their data centers"and their cooling needs"grow. Periodically, businesses must upgrade electrical and cooling systems or change the design of the data center to optimize cooling to avoid heat-related equipment failures, industry executives said. Users can generally expect to burn 1.5 watts of electricity to cool each watt of load in the facility, according to Baker.

Heat dissipation issues can be greatly improved through the proper orientation of server hardware and cooling equipment. In addition, companies should take scrutinize their server usage. Every server in use has a static level of power consumption"so that underutilized servers are increasing costs without adding value. "We are beginning to understand a useful metric by which to measure whether the power we are consuming is being consumed for a good purpose or not," said Baker.

HP offers a thermal modeling tool to customers, which combines a temperature measurement in a facility and a physical map the facility to map the flow of air throughout the data center and create a three dimensional thermal view of the facility. "By taking this information and manipulating the data in the model, we can adjust the thermal characteristics of the facility to be more efficient," said Baker. "We offer it to customers who feel like they might have a problem in the data center today or in the future or if they want to understand what might happen if they had an air conditioning failure."