In-Depth

The Disappearing Desktop: How VDI Is Changing the Game

Will desktop PCs in their current incarnation fade from view as they become increasingly virtualized?

Desktop IT managers are faced with a long list of challenges in today's Windows environments. The issues range from how to deal with Windows Vista upgrades to security nightmares, to the out-of-control annual cost of per-desktop installation, patching and management, now estimated to be in the range of $4,000 to $6,000 per year, according to Gartner Inc. and IDC estimates.

One reason for the high cost of a desktop infrastructure is complexity. While PCs have become indispensable tools, they're also increasingly complex and costly to manage from an IT department point of view. Hosted desktop virtualization, also called Virtual Desktop Infrastructure (VDI), looks to solve many of these problems.

The basic model is simple enough. Hosted desktop virtualization moves desktops to the data center by virtualizing those machines and then giving each user access to those desktop images over either a LAN or WAN network, using a display protocol such as Remote Desktop Protocol or Independent Computing Architecture. From end users' perspectives, they execute their apps and use personal settings just as if the machine were physically located on their desktops.

VDI can use PCs and laptops, or a new generation of products-thin and zero clients-that can replace the legions of Windows-based desktops scattered throughout corporate enterprises. Typically, thin clients are downscaled compute resources that lack hard drives, fans and RAM, but have drivers and operating systems. Zero clients such as those offered by companies like Sun Microsystems Inc. and Pano Logic Inc. take the thin-client concept one step further: They have no drivers and embedded OSes, requiring less management and further reducing costs-according to the vendors offering them.

VDI effectively creates a form of recentralization, harkening back to the days of mainframes and dumb terminals; skeptics say thin-client computing is basically old wine in new bottles. Still, industry leaders VMware Inc. and Citrix Systems Inc. have already seen successes in implementation. VMware points to a number of successful implementations in the health-care industry like Huntsville Hospital, where some 1,600 desktops have been converted. And Citrix has had significant success over the years selling server-based computing solutions such as Presentation Server, basically a forerunner of a hosted desktop geared toward specific applications.

The main target market for VDI is knowledge workers; the question is whether they would fight a move to thin or zero clients. In fact, the manner in which IT shops deal with important issues such as customization and personalization will have a major impact on VDI adoption rates. Taking control away from users can make buy-in difficult or impossible.

That's why many observers believe that providing the same level of customization that users now have will be critical. Aly Orady, CTO of Pano Logic, calls it "change acceptance" -- whether users will accept these new approaches. This will be a tricky area for IT managers to contend with because the hosted desktop gives much greater control over policy enforcement.

An IT No-Brainer
While the pros and cons of VDI for end users are still being debated, the benefits to IT departments are more obvious. According to VMware's Jeff Jennings, VP of desktop products and solutions, the top three drivers for hosted desktop solutions are, in order of priority: cost, management and security. Cost relates to both capital outlays for new computers -- which can be reduced if thin clients are used -- and lowered costs for ongoing management.

Improved security is another highly touted benefit, and one that's particularly useful in regulated industries like financial services and health care. High-profile laptop thefts over the last several years -- some involving highly sensitive data -- have shined a bright spotlight on the need for new approaches. With hosted desktop virtualization, security can be monitored more closely and virus threats reduced. Further, if a thin or zero client is lost or stolen, no loss of valuable data occurs because the device is stateless.

As this market grows, IT departments may have other options as well -- for example, off-premise hosting, which is basically a form of cloud computing. Instead of anchoring virtual desktops in the enterprise data center, hosting is done by a services provider -- often a telecom carrier such as Verizon or the services arm of an IT supplier like IBM Corp. or Hewlett-Packard Co. Vendors selling these types of solutions, such as Desktone Inc., refer to this as Desktop as a Service, or "DaaS."

Small, but Growing
While there's considerable buzz around VDI, much of the market is still embryonic. But most analysts expect the market to experience robust growth. One market researcher, IDC, is predicting that the market for desktop virtualization software will grow to $1.7 billion by 2011. "The potential market is huge," says Rachel Chalmers, research director with analyst firm The 451 Group.

Besides Citrix and VMware, other suppliers include Sun, Microsoft, Parallels Inc. and Hewlett-Packard Co. (largely through resale of VMware and Citrix products as well as its thin-client business). In addition, there are a slew of start-ups in the game including Desktone, Pano Logic and Qumranet (recently acquired by Red Hat Inc.).

VMware was the first company to market with VDI. According to Jennings, "the reason why VMware got into the VDI space was because of our Citrix customers who were asking for options because they felt there were gaps in what they had."

VMware VDI (renamed VMware View) is a combination of products that work in concert. The three main elements are the ESX hypervisor, VirtualCenter management layer and Desktop Manager. But other VMware products, such as VMotion, play important roles. VDI was augmented last January with Virtual Desktop Manager 2, which provides desktop-specific management capabilities and serves as a connection broker.

VDI can be configured with either PCs or thin clients. If the latter, VMware has a large number of partners including

HP, IGEL Technology Inc., NEC Corp., Pano Logic, Sun and Wyse Technology Inc. Laptops tend to be a bit of a monkey wrench in the works, but the company is working to fix that. According to Jerry Chen, senior director of desktop products and solutions, VMware is working on a project called "offline VDI." "This is the ability to stream the virtual machine from your server, check it onto your laptop, work offline and then check it back in," explains Chen.

The company also unveiled its vClient initiative at VMworld 2008, which includes the concept of universal clients. The key idea is that desktops and data follow users, regardless of which end-point device is used. Other VDI products on the roadmap for 2009 include VMware View Composer, for image management and offline VDI.

Figure 1
[Click on image for larger view.]
Figure 1. VMware's virtual desktop infrastructure components.

The 'Big Three'
VMware is the market leader, but competitors are racing to catch up. For the short term, both Citrix and VMware are considered to be the best-positioned companies to capture market share over the next few years. Competition will be robust.

Although VMware can claim to be the market leader in this space, it's a claim that has yet to be fully validated because the market is so immature. Citrix could quickly become a major VDI player, for example. Its long-term record of success with Presentation Server gives it a strong base of Fortune 500 companies along with small to midsize businesses.

Citrix's VDI prospects were boosted by the acquisition of XenSource in late 2007. XenSource included a product for full-hosted desktop virtualization (rebranded XenDesktop). XenDesktop was formally announced in October 2007 and has a pricing structure designed to undercut VMware's offerings.

Rounding out the "Big Three" offerings is Microsoft. But just as the company is playing catch-up in server virtualization, it's lagging even further behind in hosted desktop compared to the competition. A key issue is whether Microsoft will continue to rely on its partnership with Citrix to fulfill this area or will develop its own products internally. At this time Redmond taps Citrix for both a connection broker and XenDesktop, says Zane Adam, senior director of Integrated Virtualization at Microsoft. According to Adam, a partial hosted desktop solution is currently available for Windows Vista desktops under a new license called the Vista Enterprise Centralized Desktop (VECD).

Looking Ahead
Unlike the market for server virtualization, which has a relatively straightforward value proposition, the market for hosted desktop virtualization has its uncertainties. Will users warm up to having their PCs replaced with thin clients or other options, or to decreased control over how they use, select and configure apps?

Mobility is another issue that has to be addressed. By some estimates, the number of laptops being purchased is at around 35 percent and increasing. It's unclear how this trend will square with growing deployment of thin or zero clients for knowledge workers. If VMware's vClient initiative and offline VDI option is successful -- still only on the drawing board at this stage -- many of the challenges involving mobile workers will have been addressed.

Before hosted desktop virtualization becomes widely deployed in enterprises, these and other issues will need to be sorted out. Hosted desktop virtualization will clearly not be as straightforward as server virtualization. For example, a recent Yankee Group survey noted that "desktop and application virtualization ... will experience slower, more measurable adoptions rather than the tidal wave of deployments that characterized the server virtualization market."

The survey said that "just over one-third or 34 percent of the survey respondents indicated that they plan to virtualize their desktop PCs and laptops; and only 32 percent of the 34 percent said they have already deployed or are currently in the process of virtualizing their desktops." But regardless of the speed of adoption, it seems clear that IT shops will need to find viable solutions to the increasing complexities of the traditional client/server model that has bloated both the operational efficiency of PCs as well as their management costs. In the eyes of its proponents, hosted desktop virtualization can be a major part of achieving this goal.

About the Author

Tom Valovic is a freelance technology writer.

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