While a virtualised desktop infrastructure (VDI) may promise some advantages for the enterprise, the approach is still more expensive and less responsive than standard desktop PC deployments, contends a Microsoft executive in a blog entry Monday.
"Overall, when compared in a well managed office worker environment, VDI is generally 9 -11 percent more expensive than the corresponding PC environment," wrote Gavriella Schuster, senior director of the Windows commercial product management group.
Schuster also noted that VDI users complain of a "diminished ... experience," due to the fact that "application performance is directly dependent on network connectivity."
The post is an attempt to help customers determine when they should use VDI, client virtualization or application virtualization, Schuster said in an interview. Microsoft will get the operating-system licensing fees no matter how the OS is deployed, so the company is "agnostic" as to the approach customers use to deliver the OS to the user, she said.
"Our enterprise customers have complex environments, and they have many different kinds of users. So there are times when VDI makes sense," she said. "Every customer will have a VDI, and we're trying to help them understand what it is good for, and what it is not good for."
The cost estimations came from a survey of about 100 enterprise customers who had spoken with Microsoft about their VDI deployments.
Not everyone has reached the same conclusions, however. Computer Sciences Corporation (CSC) compared the costs of running 5,000 desktop computers with 5,000 VDI instances and found that VDI cost, on the whole, 20 percent less, said Phil Grove, CSC's global director of end user services on desktop virtualization, in a recent interview.
CSC manages about 1.2 million desktops for its customers, including some VDI instances. In some cases VDI can even be faster than desktops, depending on the network and the data center, Grove said. In other cases, due to bandwidth and processing needs, there will be some users who "will always require a workstation."
Microsoft recently partnered with Citrix to offer VDI solutions. But Schuster's post advised only to use VDI in "specific scenarios."
For instance, VDI makes sense in those cases in which workers have to maintain two desktop computers in two different locations. It also makes sense for shift work, when a single PC is shared by multiple employees.
The blog post deflates some of the commonly held assumptions about VDI's benefits for general enterprise use: It is true that VDI reduces hardware costs. But it also increases software costs. It reduces help desk costs, but increases desktop engineering costs as well, the company argued.
In the interview, Schuster also mentioned that Windows 7 "alleviates a lot of the reasons" that may spur organizations to consider moving to VDI, especially doing so with their copies of Windows XP or Vista.
One reason managers state for considering VDI is how it may reduce the number of different operating system instances that have to be supported. One OS can be used for multiple clients. But Windows 7 image management has been streamlined so that administrators do not have to build a core image for each unique machine. This reduces the total number of images that must be maintained.
Windows 7 also has new features that aid in power management and remote assistance, two other strengths attributed to VDI. Her assessment seems to fall in line with some other appraisals of VDI.
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