When there was the PBX, there was the switch room. With IP Telephony, there is the data center. Data center real estate is expensive. A goal of data center operators is to pack as much equipment per square foot as possible in the data center.Since IP Telephony is now server based, the server selection should include the energy costs for operating that server over its useful lifetime. The Tolly Group and Nortel have published reports on the energy requirements of many IPT servers. There are definite differences in IPT server energy consumption.
The high density data center situation is changing. The average data center consumes about 575kWh per square foot per year at a cost of $60 to $110 per square foot per year. Part of the increased power cost is the amount of heat that must be handled. About 43% of the power bill in a data center is for cooling the equipment. An IDC survey conducted in 2009 found that 21% of the data center managers surveyed consider power and cooling requirements as their # 1 issue.
How much can be packed in a rack appears to be coming to a saturation point. As the computing power has increased for servers, so have the energy requirements. Can doubling the equipment density be sustainable? Probably not.
One of the newer trends is improving server power efficiency. Another is scaling the power requirements to the actual computing power in use. This means as the workload decreases, the power requirements decrease proportionally. A third change is that the maximum operating temperature for data center equipment is rising, thereby reducing the cooling costs.
Prior to 2004, the operating temperature was 72 degrees Fahrenheit. In 2008, it was 81 degrees Fahrenheit according to the ASHRAE Technical Committee 9.9, American Society of Heating, Refrigerating, and Air-Conditioning Engineers. However the older the equipment, the lower the required operating temperature.
Here are some recommendations to help with the data center density, power and cooling issues:
* Directly charge the data center operations for their energy bill. Data centers are usually charged by space, not power consumption. Most data center energy costs are hidden in the enterprise overhead. If the data center manager pays the bill, this will provide a major incentive to manage the energy costs.
* Consider replacing your servers. New servers increase the computing power per square foot. They also consume less power and require less cooling. Look for EPA Energy Star rated servers. The Energy Star servers may cost more but the savings in operating costs, power and cooling, will more than offset the initial cost.
* Look for new servers that come with power management technologies. These can reduce the power consumed during idle times. Your may already own this technology. Many data centers have not turned on this feature.
* Virtualize your server environment and retire some of the servers, thereby reducing the energy costs. An IEEE study of server utilization demonstrated that the average server is less than 35% busy (source: IEEE Computer magazine, December 2007, "The Case for Energy-Proportional Computing"). Many IPT vendors can now virtualize their IPT software in a single server. Others can virtualize their software in servers that support non-IPT applications.
* If the density of equipment continues to increase, parts of the data center may have to be redesigned for water cooled operation. This is more efficient, but the capital cost of installing water cooled systems may be a deterrent.
* Data center air conditioning uses fans or air handlers. This is to circulate the cooling air under the raised floor or through ducts. Reducing the fan speed about 12% to 13% can reduce the power consumed by the fans in half.
* Install temperature monitors to find both the hot spots and the over-cooled areas. This will provide the information to better balance the cooling.
* Place perforated tiles near warmer areas to focus the air flows where needed.
* Consider operating the data center at a higher temperature. This does not save server power, but can reduce the cooling bill. Unfortunately, the higher temperature may cause the fans to run faster thereby negating some of the energy savings. There will still be an overall energy cost reduction. Most equipment designs do not allow for operation over 81 degrees Fahrenheit operation.
So the future data center for high performance systems will probably be water cooled. Less dense data centers will remain with air cooled systems. Another possibility is to move the data center to a location where the real estate space is cheaper and the energy rates are lower such as in Washington State.
