Ten reasons to think twice about virtual desktops

These limitations in server, storage and networking assume, of course, that users still want access to the richness of the applications they have grown used to on the desktop.

7. Application performance

Understandably, most users revolt if "upgrading" to an inferior user experience.

"Applications with multimedia, for graphics or 3D modelling, still work best on a dedicated machine," Margevicius said.

While improvements are being made to improve the multimedia experience on the virtual desktop, it will be another 12-18 months before these issues are ironed out, he said.

For now, such limitations restrict the utility of virtual desktops to call centres and kiosks, he said, rather than traditional office workers.

 6. Licensing headaches

Margevicius said that too many CIOs assume that the software licenses that exist today on a physical PC are translatable to a virtual PC instance.

"The reality is that is not the case," he said. "Microsoft, for example, has very specific requirements around Windows licensing - a license is physically tied to a given device and is not transferrable."

Some customers assume they are covered under the 'Software Assurance' maintenance they pay Microsoft, which is around US$40-US$60 per device per year.

"But in fact, to deploy virtual desktops on your thin client or iPad, you require yet another license which is not covered by Software Assurance," he said. "It's called VDA or virtual desktop access and it's a brand new license this year. It will cost you US$100 per device per year."

Margevicius said that Microsoft is using the hype around virtualisation to shift to an annuity business model.

"Microsoft is very sneakily changing the pricing model for Windows," he said. "On the traditional desktop you purchased a perpetual license and Microsoft could never charge you another dime.

"But by doing virtual machine licenses, Microsoft has very sneakily changed its model to an annuity scheme. Like Software Assurance, VDA is a non-perpetual license - but by the way, the license is still tied to the device.

"They get you," he told Symposium attendees. "People ask me, when is Microsoft going to enter the virtual desktop market? I answer that they are here. They are already charging you for doing nothing."

5. What about offline access?

While concerns are often raised as to how much time is wasted on the internet, the reality for many information workers today is that a loss of internet connectivity has a serious impact on productivity.

But in the traditional fat client world, there are still tasks users are able to perform when offline - replying to stored email messages (queued for re-connection), for example, or working with office productivity tools -- assuming the company hasn't shifted these to the cloud.

So beyond concerns users might have about application performance or indeed having some level of control over their desktop environment, the lack of offline access to files and applications can be a barrier to user adoption.

"The statistics show that 40 percent of users are buying a PC notebook" for desktop use, Margevicius said.

"There is obviously a requirement to be functional when you are off-site or off-line for whatever reason. And we are still 18-24 months away before an offline version of a virtual desktop is viable."

4. Internal politics

There are other cultural barriers to deploying virtual desktops.

The PC fleet has historically been the domain of a desktop or end-user computing group within large organisations. Some of these IT staff will be reticent to hand off desktop control to a data centre team.

And more importantly - even if the desktop team was willing - the assumption is that the data centre team wants the headache of having to cope with managing end user computing needs.

"Remember, as you design your hosted desktops, keep in mind that scale matters," Margevicius said. "It's not just about adding a server - it's about adding thousands of users to manage - and more storage, space, power and cooling needs to be allocated within the data centre design."

He warned that a large organisation's PC group is "not people who have experience with servers" and may need to be led in some respects by the advice of the data centre team.

"It's much bigger than a PC implementation and touches many places," he said. "When you create virtual desktops, it is an infrastructure play that crosses all disciplines."

Read on for the top three reasons to think twice about virtual desktops...