Creating energy-efficient data centres

Thada Savetsila is country manager of EMC Information Systems (Thailand)

Ten years ago, a typical server consumed 100W of power. Today, the average server consumes four times as much. Servers use about 30 per cent of their peak electricity consumption while sitting idle, which is often more than 80 per cent of the time.

Making things even worse, the density of servers per square foot has doubled over the past 10 years from 7 to 14 servers per rack.

According to IDC, the overall power density of a data centre is increasing by 15 per cent per year. All the electricity consumed by servers is transformed into heat, so to prevent data centres from turning into hot houses, about 125 per cent more electricity is consumed by cooling equipment.

The increase in energy costs and concerns over the availability of electricity are forcing data centre operators to give serious consideration to managing the energy efficiencies of their facilities. Through systematic planning and effort, it is possible to reduce the electrical bill for running a data centre by up to 90 per cent.

Operating an energy-efficient data centre

One of the simplest operational steps towards energy efficiency is to retire obsolete and redundant IT systems. Many data centres continue to operate legacy servers for testing or archival purposes. Without careful inventory, it is easy to lose track of these servers. In large data centres, it is not uncommon to find servers running, but with no users.

Even if these machines cannot by physically retired, turning them off when they are not needed will save power. Similarly, many of the associated systems that support a server are often not run inefficiently at their full operational load.

The logic in under-scrutinising such devices is that there is a surplus capacity for use in case of need. It would, therefore, be far more energy-efficient to run these devices as recommended by the manufacturer and keep a store of unused units to provide the needed surplus capacity, on a need-to basis.

Planning ahead

Running fewer physical servers is one way to reduce a data centre's power consumption. Unfortunately, most data centres run applications that need to operate on different operating systems and under specific configurations. Server virtualisation is the solution to this problem and is an important planning step towards an energy-efficient data centre.

Virtualisation allows a single physical server to host several applications in whatever environment those applications need. The physical server is host to multiple virtual servers where each can run a different operating system and is configured to suit the application's needs. Through virtualisation, some data centres have consolidated servers by as many as 20:1.

As well as the energy savings achieved by unplugging unnecessary servers from the power grid, virtualisation further reduces electricity consumption because fewer servers means less cooling is needed.

It has been conservatively estimated that for every workload moved from a physical to a virtual environment, customers can save about US$290 (Bt10,358) in electricity costs, and about $360 a year in cooling costs.

Beside the effect on the company's bottom line, virtualisation can also have a positive outcome for the environment. The $650 saved per virtualised workload represents 8,000kWh of electricity saved.

Other steps

A further way to improve energy efficiency in data centres is to introduce a policy of managing information as it ages, better known as information infrastructure management. This is achieved with tiered storage infrastructure, software and services to enable consolidation of numerous islands of storage, increased storage utilisation and avoidance of data duplication, all of which creates greater energy efficiency.