Virtual unrealities exposed

Do you need it?
Virtualisation may soon be everywhere, but that doesn't mean it's for everyone. There are inherent limitations to the technology — such as the overhead involved — which make it unsuitable for workloads with heavy, continuous processing or I/O demands.

Microsoft's Biehler points to four key uses for virtualisation: server consolidation in the data centre and branch office; consolidating and re-hosting legacy applications; automating and consolidating software test and development environments; and simplifying disaster recovery planning. "If your requirements are one of those four, it's worth considering virtualisation. If not, it's worth first validating whether it really makes sense to virtualise."

More important, though, is to remember that virtualisation is just one means of achieving infrastructure that's reliable, adaptable, doesn't cost a lot and is easy to manage. Virtualisation may be a part of the way to reach that goal, but many companies may find they really just need to address more basic problems.

"When you move to a virtual environment, that doesn't mean it's more efficient," says Gartner's Dawson. "If you take a pile of rubbish and you refine it, you get refined rubbish. People have to learn that they need to discover their portfolios before they virtualise them. The right approach may be to send it off and not touch it."

Also the level of management discipline found in x86-based data centres is often lacking, compared with that in the mainframe and mid-range worlds, says Ovum's Barnett. "If the environment is subject to little or no management discipline, if you don't have that governance and those processes in place, then actually, virtualisation and clustering are probably not going to help you. You need to sort the mess out," he says.

Just moving to network-based storage may boost reliability so that companies may have little incentive to go further, Barnett says.

That said, the benefits of virtualisation will almost certainly ensure its rapid growth for the near future. "VMware now has references for companies using the technology on a decent scale. They can point to people really doing it and benefiting from it," Barnett says. "That is always going to result in an acceleration of usage and adoption. We expect interest in virtualisation to keep accelerating."...

(See the next page for a overview of the leading players in virtualisation)