Free air cooling helps Telco with green data centre

As data centre capacity in London is wrung dry, there is increasing development outside the capital.

"We have eight data centres around the U.K., and our London data centres are very full. Space in London is very constrained; it is the same throughout the marketplace. A lot of companies are now starting to build in Reading and outside the M25 corridor; people are trying to move away from London, because it simply hasn't got the power to be able to provide the data centre infrastructure," Haynes said.

The data centre power-capacity problem
Before environmental issues reached prominence -- when power was cheap and plentiful -- London had a lot of excess capacity. When the Docklands printing works closed, there was even more. But as the telecom sector began to move into the area, many of the buildings in the Docklands area that had been built for office space were turned into data centres -- for example, Telehouse.

Companies wanted to be close to Telehouse, largely for latency reasons. Now they are going where the power supply is.

Kingston Communications looked to legacy sites to convert to data centres: "Bristol was an old point of presence for our switch; it was effectively an old telecom switch site which had additional capacity, which we started to provide connectivity and hosted services out of," Haynes said.

"What we are seeing in terms of demand for hosting in the Bristol area is there are quite a few large companies working out of Bristol and Exeter, large population areas, who are looking for carrier-grade hosting, and there aren't that many people in this area who have a telco-grade hosting service."

It can be difficult to tick off the green boxes with retrofit data centres, but Kingston Communications was not in a position to consider scrapping the old switch building and rebuilding to modern environmental standards. The site was too small to justify that. Instead it has based its green data centre on environmentally friendly free air cooling and heavy use of virtualisation.

"Cost is the killer for us, and for a whole new data centre from scratch we would be looking at £10 million upwards, depending on the stack. It is cheaper to expand the existing facilities than it is to start from scratch," Haynes said. The site has approximately 100 racks.

The company has some green data centre efforts underway, including taking free cool air from outside and bringing it in, rather than using expensive air-conditioning technology. Some claim that free air cooling can save 40% of the energy of a data centre, but Haynes said it is too early to measure the savings and return on investment of free air cooling at the Bristol data centre.

The site will have industry standard power, heat and humidity tolerances of between 2.5 kW per rack and 4.5 kW per rack, the heating will be 20 degrees plus and minus 2 degrees, and humidity 50% plus or minus 5%.

Haynes recommends caution when considering products that claim to push those tolerances. "Everyone has been hit by the move towards high-density machines and requirements on cooling. There are solutions out there at the moment that can provide up to 20 kW per rack. But if you actually look at the footprint, they take about three or four racks to do that, whereas if you simply take three or four racks and put a single blade server in each, you achieve the same sort of return on investment and also it is cheaper for us."

Real power savings from virtualisation
While the Bristol data centre does what it can to minimize data centre cooling costs with clever building technology, Haynes believes the real power savings are being made through virtualisation.

"We are VMware's second largest supplier in the U.K. as a service provider, so we provide a lot of virtualised machines. We have examples of about 60 Web servers sitting on an infrastructure of three machines, and we are reducing the amount of hardware and therefore power. Rather than using a lot of servers, we consolidate down to far fewer. We have a lot of government customers who are starting to make a lot more noise about green data centre initiatives and the virtualisation is a strong story."

He added, "The majority of the private sector says that while green is quite important, the fundamental thing -- particularly in these times -- is there needs to be a reduction in cost. Green doesn't really take a high priority."

In the private sector, the Bristol data centre's customers are a cross between local legal institutions and service providers. "We provide the managed service ourselves in London but we don't do it in Bristol, so these guys actually have a relationship with the customer historically," said Haynes.

He described complying with the latest environmental standards such as BREEAM (the BRE Environmental Assessment Method) and LEED (Leadership in Energy & Environmental Design) as "a significant amount of work for anybody to meet from an existing data centre."

"Most data centres were built in the '90s when there was no real focus on any environmental issues, so that is a lot of retrofitting of our data centres."

Tracey Caldwell is a contributor to SearchVirtualDataCentre.co.uk.