Sun has upgraded three of its datacentres in the USA, UK and India to make dramatic electricity savings and cut its carbon footprint. It joins IBM and HP in offering its own datacentre experiences as a green example to its customers.

Sun has consolidated datacentre facilities in Santa Clara, California, as well as in Surrey, UK and Bangalore, India. The new datacentres occupy 133,000 square feet of space, slightly less than half the original 267,000 square feet.

There were two main aspects to the new datacentre designs: server consolidation; and cooling efficiency advances. In the Santa Clara datacentre Sun has replaced 2,177 older servers with 1,240 newer multi-core SunFire T1000/T2000 and x64 servers, all running Solaris, to both reduce power needs by nearly 80 percent yet increasing computing power by 456 percent.

It is using Solaris' virtualisation features to, in effect, replace physical servers with virtual servers.

The cooling system employs a variant on the hot aisle / cold aisle design, with closed pods containing racked computing equipment These need less cooling power than a traditional design, which tries to keep an entire datacentre at a homogenous temperature through standard air-conditioning. Only the hot areas of the pods are cooled by heat exchangers which take heat outside the datacentre.

Inside the pods there are temperature sensors for individual servers and the control system can focus cooling dynamically on hot spots.

Some storage consolidation took place as well. Older disk arrays were replaced with StorageTek 3000 and 6000 arrays using 144GB Fibre Channel drives. These offered higher performance and capacity increased by 244 percent although 70 percent fewer arrays were used.

The company estimates that these server, storage and cooling initiatives will reduce its carbon emissions by about 4,000 tonnes a year, shaving 1 percent off its annual carbon footprint. The Santa Clara datacentre will pay for itself in three years.

The cost of the Santa Clara datacentre project was helped by a near $1 million rebate from the local power company.

Several European datacentres were consolidated onto a single UK site at Blackwater, a single pod in fact. One hundred older servers were replaced by 80 newer ones connected to a StorageTek 9985 storage area network (SAN) array.

Sun has information about its eco-responsible data project on a micro-site. It is announcing 'Eco Ready' services to help persuade customers to follow its example. The company says it is also considering fuel cell technology, such as that used by Fujitsu in Sunnyvale.

Sun says that it has expansion space capability in the new centres should their workloads increase.