4. Multimedia support
In addition to network concerns, a lack of good multimedia support has so far prevented desktop virtualization from being useful for employees with needs beyond the usual office tools.
Citrix promises rich graphics for virtual desktops with its HDX technology, and VMware has tried to catch up on that front by using Teradici's PCoIP protocol. Microsoft has also improved multimedia support with Remote Desktop Protocol version 7, but in general virtual desktops still don't provide as good an experience as dedicated desktops and laptops.
VMware customer Scott Lowe, CIO of Westminster College in Missouri, is a VMware customer for server virtualization, but isn't convinced PCoIP can handle the flash and other multimedia needs of students.
"They need to make sure the desktop experience closely mimics a physical desktop exp as possible," Lowe says.
In VDI deployments, "anything flash-based is terrible. Streaming audio is not good by default," Powers says. Multimedia was the first big hurdle Powers says he had to address, noting that video announcements from the Cox CEO just didn't look right on virtual desktops. Powers improved performance by using Wyse's TCX multimedia software suite.
"It's not perfect, but it took our VDI environment from being at a dead standstill to pushing it forward," he says. Cox is still relying on version 6 of RDP, "which is not the greatest," Powers says. "If I put this in the back office for some of our analysts, I don't think they would appreciate it too much."
Desktop analysts have been keeping a close eye on RDP version 7, one of the new features in Windows 7.
Previous versions of RDP do a nice job with DirectX-based applications, but don't support multimedia redirection with flash, says Eric Hanselman, CTO of LeoStream, which makes a connection broker for virtual desktops.
"RDP 7 is a "good enough" protocol for many remote access use cases," Wolf says in a Burton Group report. "Expanded support for Adobe Flash and 3D graphics make it far superior to previous RDP versions."
5. User experience
This may seem obvious, but analysts and IT pros say virtual desktop projects too often ignore the user experience during planning phases.
"Where we see stumbles is when folks create small isolated islands of virtualized desktops, without thinking about what it is their users do day to day," Hanselman says.
General task workers, perhaps 40% of all users, are pretty good targets for virtual desktop projects, says Phil Grove, global director of end user services at CSC, an IT outsourcing firm. The rest will require specialized attention, or may not be candidates for a VDI deployment.
"Power users are not that amenable to locking down the environment. They're a more challenging use case," he says. "It will probably always be true that not everyone can get a virtual desktop because it's not appropriate for all use cases."
Even when the technology is sound, it may be difficult to convince users that their virtualized desktops are an acceptable alternative, says Duarte of Universite Rennes 2. IT pros need to spend some quality time with users and show them what virtual desktops can do that regular ones can't, he says. For example, users tend to be impressed when they see that when a virtual desktop has an outage, it can be restored in exactly the same state at which the connection was lost.
"Convincing administrative people to use thin clients is very hard for us, to convince them that they can do the same things that fat desktops do," Duarte says. "If the user doesn't want to use the thin clients, the project is not viable."