Making Desktop Virtualization Work with VDI

By Matthew Sarrel  |  Posted 2010-02-19

Making Desktop Virtualization Work with VDI

There is no denying that virtualization is a hot topic in enterprise IT, but when it comes to adoption rates, not all types of virtualization are created equal. While it would be difficult to think of an enterprise that hasn't embraced, or at least piloted, server virtualization, the same cannot be said for desktop virtualization.

The ROI for server virtualization is well understood in terms of server consolidation and better asset utilization, and some of the same benefits can be had through VDI (Virtual Desktop Infrastructure), the form of desktop virtualization that most closely resembles the type of server virtualization enabled by products such as VMware vSphere and Citrix XenServer.

In a VDI scenario, desktop operating systems and applications run on virtual machines located on a server, and users access these machines remotely. Users can run thin clients to access their virtual desktops, or use full-fledged Windows, Linux or Mac hardware regardless of the operating system running on the virtual desktop.

This model allows enterprises to separate the operating system and applications from the hardware, increasing flexibility and mobility, for example by providing a full desktop experience over RDP (Remote Desktop Protocol) on a Windows Mobile device.

The use of VDI holds great promise as a way of easing the pain many enterprises feel while administering tens of thousands of physical desktops. You know the pain I'm talking about. Provisioning physical machines, asset management, hardware and software configuration management, operating system and application installation and patching, cleaning up malware, reimaging, the list goes on and on. Industry analysts estimate that these activities cost enterprises anywhere from $3,000 to $6,000 per desktop per year. Roughly half of this cost is borne by IT departments and the other half comes in the form of lost user productivity.

VDI centralizes and standardizes distributed desktops on servers in the data center. This has many advantages, such as reducing the cost of physical desktop acquisition and maintenance. Typical business applications, such as some office productivity applications, e-mail and Web browsers, will run just as well in VMs as they would on physical desktops. Consider using thin clients in public places and for shared workstations, for example in kiosks and call centers.

VDI also provides excellent business continuity, as "desktops" are available any time from anywhere. Employees can easily be moved to a remote location or work from home. Standardizing desktop configurations across different platforms and devices minimizes downtime during periods of potential service interruption.

Increased business agility is another advantage of VDI. Flexibility is the name of the game for businesses that want to survive this recession. The ability to provision or relocate a desktop with a single mouse click opens new opportunities for businesses. Users can buy whatever hardware they want and still have access to the applications they need.

As the desktop environment is abstracted from the physical devices on users' desks, management and updates become much less resource-intensive. Estimates indicate that VDI can reduce desktop TCO by anywhere from 15 percent to 35 percent. Who wouldn't want to trim that much off the desktop support budget?

VDI: Heres the Catch


Unfortunately, it isn't that straightforward. Designing, purchasing, installing and maintaining a VDI solution and the infrastructure needed to run it (servers, storage, network, security) can cause an enterprise to rack up enormous capital and operating expenses.

This isn't simply a matter of downloading a free hypervisor and building a few images. You'll need the storage to house all those images and retrieve them quickly, so you'll have to add to your existing Fibre Channel or iSCSI SAN (storage area network) or buy a new one. Pushing tens of thousands of 25GB images from SAN to server to thin clients essentially requires you to upgrade the data center backbone to a 10G-bps switched environment while running 1G bps to users' desks. Anything less and you'll risk performance bottlenecks choking the life out of your VDI initiative before it gets off the ground.

VDI changes the paradigm and increases management complexity for the desktop support team; besides, I have seen what happens when responsibilities overlap between desktop and server support groups, and it isn't pretty. You're going to have to get server, desktop, storage and network support teams on the same page in order to succeed. Make sure that management conveys the importance of working together to all of these teams.

Our sister publication, Baseline, recently reported that 30 percent of the executives who participated in a Ziff Davis Enterprise Research study expect deployment of VDI to increase at their companies. Will this make 2010 the year of the virtual desktop? Gartner seems to think so. In August 2007 the analyst company predicted that "by the end of 2010 all new PC deployments will be virtualized." In 2008 it predicted implementation by "fewer than 40 percent of target users by 2010." In 2009, it predicted that the market "will accelerate through 2013 to reach 49 million units, up from more than 500,000 units in 2009." Yet with all the interest and predictions, VDI implementation has been advancing like maple syrup on ice. Is this because of the technology, the perceptions of buyers, the general economic climate or all three?

The good news is that the technology behind VDI is advancing rapidly. In addition, servers and storage are getting faster and cheaper and are handling virtual workloads better. The cost of 10G-bps and 1G-bps switches continues to fall. My colleague Cameron Sturdevant's recent review of VMware View 4 demonstrates that the new proprietary VMware remote control protocol, PCoIP, improves performance over low-bandwidth networks. In addition, driver, printer and monitor support has been vastly improved, expanding the number of use cases for which VDI may be a good solution.

Recommendations for VDI Deployment


We make heavy use of virtual desktops and servers in eWEEK Labs. Virtualization is an excellent fit for us, but this is lab testing, not an actual enterprise with tens of thousands of desktops spread around the world. I hesitate to recommend VDI across the board. I think even the strongest proponents of the technology would agree with me. There is a ton of information available-both pro and con-about VDI. This may be a more hotly debated issue than open source in the enterprise.

But there is one aspect of the VDI discussion that sticks out like a sore thumb: the end-user experience. A key aspect of the success of any technology infrastructure initiative is end-user acceptance. Search the Web and you'll find hundreds of white papers, articles and case studies about how great VDI is for IT departments, but there is close to no information regarding real-life benefits for end users.

Server virtualization can be deployed without impinging on users' awareness, but take my PC off my desk and fundamentally change how I work while slowing me down and I really don't care what the advantages are for IT.  

During the pilot phase of implementation, it's a good idea to actively solicit opinions from users as to their experience using line-of-business applications in the newly virtualized environment. If the IT department benefits from VDI but users can't do their jobs, then ultimately the project will fail. Likewise, make sure to get buy-in from executives and keep department heads in the loop. Explain the business advantages of VDI to your organization. Don't assume that your CEO knows that virtualized desktops are a powerful disaster recovery solution. Demonstrate to users that support issues can be resolved more quickly because resources have been centralized.

A major step in implementing VDI is designing the architecture of the virtualized operating system and applications. This will ultimately affect how you build your VM images. The first step is understanding the applications and the number of concurrent users of these applications within your organization. Virtualizing the right applications for the right users before they are needed will save time and reduce friction between end users and IT. Keep an eye out for users who require unsupported applications to do their jobs. They will either need custom images built or should be excluded from the VDI project.

It's also important to establish clear criteria for success or failure before implementing VDI. In order to accomplish this, you must understand the performance of the systems your organization is currently running. We all know that no matter what you do there will be complainers. Be prepared to prove to both end users and executives that your VDI implementation is a success; that system performance has improved, costs have decreased and support time has been lowered.

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