Among the many attributes of virtualization is its contribution to lowering energy costs and lowering the carbon footprint.

In an era of much concern over power use and its effect on the environment from a specific computing and general lifestyle viewpoint, methods of reducing an IT department’s power consumption make virtualization well worth considering.

Changing server use to save power

A server uses a very powerful processor able to handle most computing tasks comfortably, but using one server for one task or application isn’t always the best way to use it. Much processing power – which takes energy to run of course – is wasted.

Virtualization allows multiple tasks to be run on one piece of hardware, so several virtual servers can be set up on one machine. This means less hardware is needed as more tasks can be undertaken on one server – the virtual servers are configured by virtualization software.

Energy saving – one server uses a certain amount of power to handle one task. In a virtual environment it will be completing several tasks and doing the job of several pieces of hardware but still using similar amounts of power instead of several servers all drawing power.

Indirect energy saving – powerful servers generate a lot of heat which has to be dissipated. This means cooling is required, and air conditioning and refrigeration incurs running costs. The lower the number of servers, the lower the cooling costs.

One possible side effect of reducing physical size in server rooms and increasing the activity on a smaller number of them is ‘hot spots’ in the data centre. If this is the case, cooling configurations will need to be considered.

Other indirect costs such as lighting in the server rooms and other power use can be reduced.

Less physical space – virtualization reduces the amount of space required to house servers, so lighting and climate control costs are reduced. The effect of requiring less staff to look after more hardware has an impact in that there will be less energy to run the office and other spaces housing more staff.

All that is required to create virtual servers is virtualization software, and to virtualize storage requires a virtual SAN (Storage Area Network) used in conjunction with a compatible hypervisor. Industry leading offerings such as VMware’s vSphere and Microsoft’s Hyper-V can be used in conjunction with SvSAN, a virtual SAN from StorMagic, to set you on a path to reducing hardware, saving power and reducing your carbon footprint.

Cost savings

Working out how much actual power you’ll save isn’t a precise science. The other factor is that of power consumption rates – equipment doesn’t necessarily consume power at its maximum power rating all the while it’s switched on, so a rough and ready ‘power used x hours operational’ wouldn’t be very accurate.

There are power use calculators online, but since some are provided by virtualization product vendors they are clearly there to help do a selling job. Some commentators have found widely differing figures are produced from different calculators.