Is your data centre an energy hog? If you don’t care now, you will soon.
Ken Brill, founder and executive director of The Uptime Institute Inc., sees the beginnings of a potential crisis. “The benefits of [Moore’s Law] are eroding as the costs of data centres rise dramatically,” he says. Increasing demand for power is the culprit, driven by both higher power densities and strong growth in the number of servers in use.
Server performance is improving faster than energy efficiency is advancing. “If we’re going to get energy efficiency rising faster than the rate of performance increase, we’re going to have to do something radically different than what we’re doing today,” Brill says.
Fortunately, there are many steps that can be taken to start reducing power consumption in existing data centres without making a huge investment or sacrificing performance or availability.
1 Consolidate, consolidate, consolidate. Consolidating servers is a good place to start. In many data centres, “between 10 percent and 30 percent of servers are dead and could be turned off,” Brill says.
Removing one physical server from service saves $560 annually in electricity costs, assuming a cost of 8 cents per kilowatt-hour, says Bogomio Balkansky, director of product marketing for Virtual Infrastructure 3 at VMware Inc. in Palo Alto, Calif.
Once idle servers have been removed, data centre managers should consider moving as many server-based applications as feasible into virtual machines. That allows IT to substantially reduce the number of physical servers required while increasing the utilization levels of remaining servers.
Most physical servers today run at about 10 percent to 15 percent utilization. Since an idle server can consume as much as 30 percent of the energy it uses at peak, you get more bang for your energy buck by increasing utilization levels, says Balkansky.
2 Turn on power management. Although power management tools are available, administrators don’t always use them. “In a typical data centre, the electricity usage hardly varies at all, but the IT load varies by a factor of three or more. That tells you that we’re not properly implementing power management,” says Amory Lovins, chairman and chief scientist at Rocky Mountain Institute in Snowmass, Colo. Just taking full advantage of power management features and turning off unused servers can cut data centre energy requirements by about 20 percent, he adds.
That’s not happening in many data centres today because administrators focus almost exclusively on uptime and performance and aren’t comfortable with available power management tools, says Christian Belady, distinguished technologist at Hewlett-Packard Co. But turning on power management can actually increase reliability and uptime by reducing stresses on data centre power and cooling systems, he says.
Vendors could also do more to facilitate the use of power management capabilities, says AMD’s Brent Kerby. “Power management technology is not leveraged as much as it should be. In Microsoft Windows, support is inherent, but you have to adjust the power scheme to take advantage of it.” Instead, he says, that should be turned on by default.
But power management can cause more problems than it cures, warns Jason William, chief technology officer at DigiTar, a messaging logistics service provider in Boise. He runs Linux on Sun T2000 servers with UltraSparc multicore processors. “We use a lot of Linux, and [power management] can cause some very screwy behaviors in the operating system,” he says.
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