Organisations looking to introduce virtualisation should look at the timescales taken to implement projects as most will take longer than expected  to achieve any return on investment.

That's according to IT services company Computacenter who surveyed IT senior staff about their experience with vritualisation and found only 4 percent of companies who had installed desktop virtualisation (VDI) projects had experienced the expected ROI. The situation wasn't much better for companies that had installed server virtualisation, with just 6 percent achieving the expected results.

The survey, which was of 130 IT decision makers, also highlighted other misconceptions with 83 percent claiming that VDI would make it easier to manage and support desktop applications, something that Computacenter pointed out was not necessarily the case.

"Organisations need to be more realistic about virtualisation projects," said Paul Casey, Computacenter's Datacentre platforms practice leader. "A lot of the people didn't achieve ROI but that's because they were mainly working with hypervisor vendor's own tools and they didn't paint a realistic picture - they're naturally biased."

However, he explained that was also because the customers were not using the tools accurately. "They'd be optimistic when they plugged the figures in," said Casey. "We would use the same tools and get a different figure - for example, the customer might have an ROI within six months, while we'd say 12.

Andy Goddard, who is Computacenter's practice leader in the workplace and collaboration business, agreed. "There are a lot of misunderstandings about: some people get a lot of benefits and some people don't get a lot of benefits. It's one thing bringing desktop virtualisation in, but it's not being managed."

It's not just about tools, however, said Casey. "Organisations have to take a longer view of virtualisation and the ROI that you get from it. There are some things that aren't easily measured. The whole ROI case is based around cost savings and that's where the ROI struggles. The real benefits are more flexible, for example, it could be that a company moves from a 1000-seat building to a 500-seat building. That sort of calculation is not so easy to work out."

Both Casey and Goddard agreed that it was important to look beyond the tools supplied by the hypervisor vendors. "We look at a variety of tools," said Casey. "For capacity management, we've found Metron-Athene to be good and Embotics' vCommander for managing sprawl - but I don't want to single out any product in particular but there are some good ones out there."

Despite these setbacks, there's little evidence that companies are holding back on their virtualisation rollouts, although there may be some rethinking to do. "There's absolutely a demand for virtualisation. I can't see any cooling off of demand. They just need to have a rethink of management and technologies. Planning from day one is key - thinking about platforms, size and scale of virtual machiness, implementing management tools, and working out how to form teams - there's a need to look at the bigger picture, not just at individual projects.