Understandably, much of the discussion on how best to limit IT’s massive carbon footprint has focused on hardware innovations, such as improved processors, liquid-based cooling, and even bamboo workstations, but according to a growing number of experts virtualisation software could play as significant a role in limiting firms’ energy consumption.

That is certainly the view of Martin Niemer of virtualisation software specialist VMware, who maintains that the greenest option for IT managers is not necessarily to upgrade to more energy-efficient servers but to instead try to reduce the number of servers they are running by deploying virtualisation software.

Virtualisation software works as a layer between the server hardware and operating system, enabling firms to run multiple servers and operating systems on one physical machine.
“The operating system still believes that it is really running on a physical server, so with this technology we can have multiple servers running on one hardware device,” explained Niemer. “This can dramatically decrease the number of servers you need in a datacentre”.

This approach could also push server utilisation rates up from the typical 10 to 15 per cent levels experienced in non-virtualised environments to around 80 per cent, Niemer argued, limiting the number of servers firms need to deploy and ensuring servers run close to their optimum energy efficiency.
Relatively few firms have rolled out virtualisation software in large-scale production environments, but, according to Niemer, those that have are enjoying reductions in energy costs and carbon emissions of up to 90 percent.

One such example is Covenant Health, a small hospital in the US that decreased its datacentre energy bill from $15,000 to $1,000 a year by virtualising many of its servers. Meanwhile, a community bank in the San Francisco area decreased power bills from $314,000 to only $37,000, Niemer added.

“As a rule of thumb, you can say that the same amount the server consumes in power is also consumed by the power supply and by the cooling for the server,” explained Niemer. “That means that in the UK you save around £340 per year per workload that gets virtualised.”