Thankfully for decision makers, the VDI market is currently very top-heavy and straightforward to investigate. Although cloud providers like ThinkGrid and Cloud Networks Australia are experimenting with hosted virtual-desktop offerings best suited to smaller businesses, the most enterprise-ready offerings still come from Microsoft, VMware and Citrix.
Microsoft VDI Suite, VMware's View, and Citrix XenDesktop all offer both types of VDI infrastructure, while Microsoft App-V, VMware ThinApp, Citrix XenApp and Symantec Endpoint Virtualization Suite deliver application virtualization capabilities.
If you're using a range of client devices, you'll also need an appropriate viewer. VDI tools allow desktops to be accessed using a Web browser, but for better performance – and to gain access to recent innovations like Citrix's HDX technology – it's preferable to add a client application like a Microsoft RDP-capable client, VMware Player or Citrix Receiver, which Citrix endeavours to port to every new device as soon after its release as possible.
Which platform you choose may ultimately depend on your existing environment: heavy Microsoft houses, for example, will prefer a VDI infrastructure that works closely with Windows Server 2008 – and can be managed using Microsoft's System Center family of tools. That company's Virtual Machine Manager simplifies ongoing management of virtual machines, while VMware and Citrix offer their own tools to ensure the tendrils of desktop management reach into the virtual world as well.
No matter how straightforward and well-integrated the tools, it's important to remember that the old GIGO (Garbage In, Garbage Out) rule applies: VDI won't necessarily fix issues with your corporate desktops. "Iif you've got problems in the physical desktop management environment and you expect to move to a VDI environment and for those problems to suddenly disappear, that's not necessarily going to happen," says Clarke.
Caveat virtualisor
Virtual desktop technology is real, and it's delivering on its promise for some. But the technology is not without its share of sceptics: Gartner, for one, has revised its cost-savings projections downwards into the realm of single-digit cost savings.
Speaking at the firm's Gartner Symposium in Sydney in November, analyst Mark Margevicius got stuck into the whole idea of virtual desktops, suggesting that barely 10 percent of PC users – and these, primarily teleworkers, call centres and sales staff – would be using the technology by 2015. Margevicius had ten reasons why companies should be sceptical about desktop virtualization:
10. Servers need significant grunt, with 7 to 9 virtual desktop users per CPU core maximum and 1GB to 2GB of RAM per user boosting server hardware costs.
9. Storage needs can be hard to project, with hard drive performance a very real bottleneck and potential logjam if, for example, five virtual desktops all decide to run a full virus scan at the same time.
8. Heavy virtual desktop usage can bring out the worst in heavily-used networks, with latency a key issue that can affect the user experience.
7. Application performance issues, and the lack of high-end capabilities, can affect user satisfaction with virtual desktops if they feel they're being downgraded.
6. Licensing issues must be reconciled: companies assuming the delivery of applications and operating systems to virtual devices is covered under existing licenses will want to check again: Microsoft, for one, recently introduced Virtual Desktop Access licenses to cover thin-client and mobile devices that aren’t covered for virtual desktop use under existing Software Assurance licenses.
5. Offline access may not be an issue within the confines of the hardwired corporate network, but for off-net or mobile workers it can be a show-stopper. Telecoms services are better than ever, but you still need to consider and plan for potential outages.
4. Internal politics can be a real issue amongst IT teams, who are used to dealing with desktops and user support, and data centre staff, for whom the shift to virtual desktops represents a significantly large volume of additional data and users to manage.
3. They're not always easier to manage. Pooled virtual desktops may provide a cookie-cutter approach to the corporate desktop, but users tend to want more customisability. There is so far no concrete way to combine the best of both worlds, so you may very well virtualise your users' desktops to find there's just as much to manage as there was before.
2. Cost-benefit analysis is difficult. You may intuitively feel that virtual desktops will save money, but how do you translate that into your budget forecasts? There are still no hard and fast measures of savings, although a good place to start is staff and time savings from reduced user support and day-to-day management.
1. The numbers don't work. Virtual desktops cost 1.4 to 1.7 times as much as a conventional desktop, by Gartner's calculations, and this makes the whole concept unpalatable for many organisations – unless there are other operational benefits that can be quantified and offset against the additional capital investment required.
By David Braue