Businesses are struggling to integrate virtualisation into their IT infrastructures, according to new research claiming to show that two-thirds of UK firms cannot identify exactly how many virtual machines they are operating.

The survey, conducted by research firm Vanson Bourne on behalf of IT consultancy Morse, looked at server virtualisation deployment in 100 UK firms with over 3,000 employees.

It found that many companies did not have effective management strategies in place to adequately track and control virtualisation, leading to virtual machine sprawl as servers are created to meet a need, but are not removed once they have fulfilled their purpose.

While just over half of companies said they had a system to keep track of virtual machines, 67 per cent of IT directors admitted that they did not know how many virtual machines they had.

"The problem is that senior management think they've integrated virtualisation, when a lot of their underlying technology isn't doing what they believe it is. So a lot of people think they have control of their virtual infrastructure when they don't, and that's worrying," said Morse senior consultant Tom Brand.

Over a third of businesses in the survey had decentralised virtual machine management, allowing various users to create and remove them at will, which Morse said might easily create a management nightmare.

Brand said that firms can avoid difficulties by focusing on best practice from the outset, planning deployments carefully and ensuring that server, storage and communications teams are all talking to each other about the resources each needs to put in place.

"A clean start involves planning and communication between the appropriate personnel, and if you do that you should be OK. But those already using virtualisation will have to backtrack and create a strategy around what's already in place," he said.

Also important is to make sure that the right policies are in place to control virtual machine lifecycles, but without losing flexibility by locking everything down too tightly.

"The nature of virtualisation is to make infrastructure more flexible, so you don't want to constrain it. You need to make sure you have governance, but also make sure you can take advantage of that flexibility," said Brand, adding that striking exactly the right balance is very difficult.

"If you can just hit a button that gives you another virtual machine, a lot of people are doing that, then not bothering to turn them off. You need to ensure that virtual machines are archived and deleted if and when necessary."

If left unchecked, sprawl can cause significant problems because virtual machines can place huge extra demands on storage, and IT departments still have to manage the operating system inside them.