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How Virtualisation Makes Data Centres Greener

A lot has been written in the last few years about how virtualisation makes data centres `greener,' but how much is hype and how much is tangible benefit that IT managers can prove - as far as it is reasonable to do so - to their line management?

At the Storage Expo 2009 event, held in London in mid-October this year, Owen Cole, technical director with F5 Networks, the financial services networking and IT specialist, explained how this is possible.

Cole pointed out that green IT is all very well, but that most organisations also have to worry about another type of green, the green on the bottom line of its financial reports.

The good news, he said, is that there is some degree of overlap between these green computing initiatives.

"Reducing power consumption and management expenses, and increasing efficiency of existing resources through consolidation and virtualisation decreases both the impact of devices on the environment as well as on IT's increasingly tightening budget," he explained.

One simple - but often overlooked - aspect of green IT is how many BTUs (British Thermal Units) are generated by any given device.

According to Cole, by decreasing the BTUs generated, there is less heat and thus less cooling required within the data centre.

Interestingly, Cole said that reducing power consumption and generation of BTUs for devices and servers in a virtual centre is something over which IT has no control.

"While IT can certainly use such ratings as part of its decision making process for purchasing, it really can't do a thing to affect how much power is consumed or how many BTUs are generated by any given device. It's simply a cost of doing business," he said.

Despite this, Cole argues that IT can make decisions, both in purchasing and architecture, which reduce power consumption and heat generation by reducing the number of servers and devices that make up its data centre.

"By virtualising blades and CPUs - essentially creating a single, powerful processing matrix - this new breed of chassis-based application delivery controller can scale nearly linearly," he said.

"This internal processing scalability means that every last drop of processing power is being used and can provide a much higher capacity than its legacy ancestors," he added.

In a virtual environment, because an organisation is better using the processing power available, Cole says that the performance per power unit is increased, making each transaction processed by the application delivery controller cost a fraction in terms of power consumption than would otherwise be possible.

IBM is also aware of the green aspects of virtualisation, as, back in the summer the computing giant teamed up with the Aberdeen Group to develop an online assessment tool designed for organisations seeking to improve their Green IT capabilities and performance.

Located at, the diagnostic tool uses Aberdeen's research into green IT and sustainability, and is intended to help companies identify potential areas for improvement, including server and datacentre virtualisation, energy efficiency and end-user collaboration.

Extrapolating this data allows the tool to recommend steps that organisations should take to address these capabilities and so achieve ROI from their Green IT investments.

According to IBM, the online tool automatically compares companies of a similar size, helping companies determine their green IT position by benchmarking against best-in-class organisations, as identified through Aberdeen's PACE (Pressures, Actions, Capabilities & Enablers) research model

In use, the online tool allows participants to complete an online survey and receive a personalised summary of how they compare, allowing them to identify the green IT strategies, capabilities and technologies used by companies with best-in-class performance.

IBM says that each survey takes around 15 minutes - there are three in total - allowing firms to see how they compare in green iT terms with other companies.

At the end of the online process, organisations then receive a customised report that allows them to develop an actionable green IT roadmap for their enterprise, as well as prioritise their investments into green IT capabilities and technologies.