How to curb IT's hunger for power

Simpson: One way to reduce the need for power-hungry hardware is to adopt server virtualisation technology

Many datacentre managers are facing limits on power and cooling capacity in addition to growing demands to reduce overall energy consumption. This combination of factors inevitably leads to a desire to improve overall datacentre energy efficiency. What changes will have the greatest impact on efficiency? Are new power and cooling infrastructures the answer, or should the focus be elsewhere on technologies such as server virtualisation?

Of course, the answer largely depends on the initial state of the datacentre. But just because there isn’t a straightforward solution does not mean you should throw up your hands in despair ­ – there are some things that all IT leaders could and should be doing right now.

These include: monitoring energy consumption; consolidating the server estate through the use of virtual servers; introducing energy-efficient hardware; exploring storage efficiency; and introducing air-side economisers for cooling.

Very few datacentre operators have a clear idea of how much energy their various systems consume. Without any accurate reading of datacentre energy use, it’s almost impossible to devise an effective plan for minimising consumption.

For example, if we assume 50 per cent of power goes to cooling, 25 per cent to servers, 15 per cent to storage, and 10 per cent for other equipment, then reducing the power used for cooling by one per cent is 3.33 times more effective than reducing storage power consumption by one per cent.

The single most effective way to reduce power and cooling requirements in the datacentre is to reduce the amount of equipment in the datacentre. The reason is simple ­ – equipment reductions count double. If you cut the number of servers by 10 per cent, it not only reduces the power consumed by the equipment, it also means less energy is required to cool the datacentre.

One way to reduce the need for power-hungry hardware is to adopt server virtualisation technology. Even a very modest deployment of two virtual machines per physical server could halve the number of servers in the datacentre. Put simply, there is no other technology that can make such a difference to datacentre energy consumption.

Take a look around your datacentre. Does it look like the place where old servers go to die? I’ve seen datacentres with Intel-based servers that should be in a museum. Old servers not only tend to gorge on energy, they can also be difficult to maintain as spare parts become increasingly hard to find. The moral here is that any server more than five years old has no business being in your datacentre, and should be replaced with new, more energy-efficient hardware, or better yet run as a virtual machine somewhere.

Storage is second only to servers when it comes to the consumption of power and cooling resources, and with storage capacity growing 50 per cent a year it will become the primary consumer if you don’t start to take steps to prevent it. So any plan to control datacentre energy consumption must take storage into account.

IT teams should consider the following steps: replacing high-performance disks with solid state storage; implementing tiered storage and archiving inactive data; and using de-duplication technologies to reduce the number of data copies created by users and by IT processes such as backup.

Most datacentres are in locations where outside air temperatures are at or below the desired temperature of the datacentre for a significant part of the year. Such facilities are prime candidates for the use of energy-efficient air-side economisers that pull in cold air from outside to maintain temperatures. Even if you can only run outside air for two months in the year, it still offers the chance to chop eight to 10 per cent off the annual energy bill.

Nik Simpson is a senior analyst at the Burton Group