Sun is preparing to tune its servers to be more environmentally friendly by introducing power management capabilities.

Speaking about the future of the datacentre at the Sun Labs Open House event in Menlo Park, Subodh Bapat, of the Sun eco responsibility office, talked about energy-efficient improvements planned for Sun servers as well as steps Sun and others are taking to make their datacentres more environmentally friendly.

Sun planned to introduce the notion of power-managed states, in which future servers would respond to a user's internal energy policies. For example, a 1-kilowatt server might be tuned to run at only 500 watts, and the server figures out how to run under that constraint, Bapat said.

"Today, our servers don't do that. They burn as much power as they possibly can," he said.

Power management also will be offered for memory components, chips, disk drives, and fans via intelligent firmware that will calibrate power. There will be states like idle and sleep states.

"We're basically going to allow customers to express policies," ranging from run as fast as possible and get the job done in as little time as is needed to take longer but burn fewer watts, said Bapat.

Datacentres, Bapat said, are undergoing substantial growth right now after what had been a down period. "About five years ago, you could buy datacentre space for really pennies on the dollar. Today, datacentres are premium real estate," said Bapat.

But there are issues with heat generation and whether local electric utilities can supply enough power for these datacentres. The centres are being configured such that they have hot and cold regions abutting each other. "That's not a very efficient way to operate a datacentre," because power needs to be supplied everywhere," Bapat said.

Sun at its Santa Clara facilities organised server racks into enclosed pods into a central aisle; hot air is then pumped directly into the air conditioning unit. Containment of hot and cold aisles is among the moves that can be made.

Other suggestions include running datacentres at off-peak hours for activities such as batch jobs and even siphoning off the cheaper night-time megawatts during the night to freeze water. During the day, air conditioning use is cut by running the hot air off the ice.

Another example cited was having ambient air run through a network of pipes. The air comes out at 65 degrees. "People are doing that to essentially get free cooling and put that in the datacentre," Bapat said.

Bapat also cited another unusual example. A university with a datacentre and a sewage treatment plant was expending 2 to 4 megawatts of power to cool down water that had heated up to 98 degrees in the datacentre and another 2 megawatts to heat up water to 98 degrees at the sewage treatment plant. This was an ideal temperature at which algae can break down sewage. So, the user site just coupled the two, funnelling the heated water from the datacentre over to the sewage treatment plant, said Bapat.