Microsoft is pushing desktop virtualisation as a way of making Windows 7 play nicely with old applications, especially those written for Windows XP. So now that the technology has been "blessed" by Microsoft, should we expect a desktop virtualisation boom?

Probably not, most experts agree. "Adoption is ramping up slowly due to complexity and cost," according to a recent presentation by Forrester Research.

That said, though, there will likely be an uptick in the acceptance of desktop virtualisation for a couple of reasons. First, more vendors are offering virtual desktop infrastructures, which give each end user a private "desktop". VDIs use the same kind of hypervisors that allow many virtual machines to run on a single physical host. But rather than running five- or 10-server VMs on one physical server, a VDI can run 50 PC operating systems, each of which serves a single end user.

Desktop virtualisation at a glance

Definition: A computing environment that is abstracted from the end user's PC. It consists of an operating system, applications and associated data.

Type 1: Local desktop virtualisation. The entire desktop environment - essentially a very large file - executes in a protected "bubble" on the end user's PC. Vendors in this market include Microsoft, MokaFive, Parallels and VMware.

Type 2: Hosted desktop virtualisation. The desktop environment executes on data centre servers, alongside other virtual machines. Vendors in this market include Citrix, Desktone, Microsoft and VMware.

ROI: The nine-month ROI that vendors tout may actually be more like three or four years, because the upfront infrastructure and licensing costs far outweigh the upfront benefits. So include other benefits, such as increased security and lower support costs, to make your case for virtualisation.

Prediction: "The revolution will take years, but virtualisation is the future of the corporate PC."

Source: Forrester Research.

The other big change is support for peripherals, multimedia and other web- and PC-focused technologies. Those haven't been available to users of shared-image terminal-services types of systems - that is, traditional desktop virtualisation set-ups - but nowadays most other users think they can't live without them.

"Improvements in the user experience are really a big deal in making desktop virtualisation more acceptable," says Andi Mann, an analyst at Enterprise Management Associates (EMA).

Giving end users all the benefits and all the capabilities they'd have on stand-alone machines - including the ability to add or update their own browser plug-ins, media players and other "extraneous" software - could overcome most of the objections of business units that have kept virtual desktops out of the mainstream user base, Mann says.

Updating Old PCs

The fact that some companies are unwilling to upgrade their PC hardware so that it's capable of supporting Windows 7 could also help make virtual desktops more popular, according to Chris Wolf, an analyst at Burton Group, now part of Gartner.

Implementing Windows 7 requires upgrading hardware, updating custom-built software, training end users and updating the security on PCs running the new operating system. That process can be so expensive and disruptive that many companies are asking consultancies like Burton Group to evaluate whether it makes sense to leave end users on their present hardware and upgrade them by running Windows 7 as part of a virtual-desktop connection, Wolf explains.

What IT managers want from desktop virtualisation

Top Five Expected Benefits

IT managers expect to cut costs when they implement desktop virtualisation.

1. Reduce hardware costs

2. Reduce administrative/ management costs

3. Improve flexibility and agility

4. Improve staff mobility

5. Improve security and compliance

Top Selection Criteria

IT managers want to select desktop virtualisation products that will be easy for employees to use and easy for IT to manage.

1. Ease of user for end users

2. Ease of management

3. Support for systems/apps

4. Scalability

Source: Enterprise Management Associates Inc. survey of 102 IT professionals who are familiar with desktop virtualisation, August 2009

Connecting end users to a new operating system on a server can more than double the life of an ageing PC while still giving end users all the power and support for new software and new technology they want, according to Peter Graves, CIO at Independent Bank Corp.

About 90% of Independent Bank's users already have shared-session virtual desktops from Citrix Systems, and Graves says that adding the other 10% will be no great leap once the technology supports the customised software and peripherals they need.

The same is not true of most companies, many of which have little history with or understanding of virtual desktops and are just getting used to virtual servers, cloud computing, and cost- and labour-saving IT tactics, Mann says.

This may explain why desktop virtualisation has yet to take off even though it has been around for at least a decade.

Numerous surveys of corporate IT managers reveal tremendous interest in desktop virtualisation but not much adoption. "We've been looking for a sharp inflection in sales of virtual desktops for three years," Mann says, but it hasn't taken place.

What's the hold-up? An EMA survey of 102 IT managers last year found that the top three barriers to desktop virtualisation are all human factors: lack of skills or knowledge, internal political issues, and a lack of resources.

The Role of Windows 7

Banks, hospitals, schools, government agencies and other enterprises that have tight budgets or are strictly regulated are the organisations that are most likely to embrace desktop virtualisation.

Companies that have resisted terminal-services-based virtual desktops as too clunky, too restrictive and too off-putting to independent-minded workers make up an untapped market of prospective customers that vendors hope will rush to adopt new desktop virtualisation products, Wolf says.

All of those potential virtual desktops don't have to run on Windows, let alone Windows 7, Wolf acknowledges. While running virtual Windows 7 desktops would be cheaper than the real thing, it's still not as cheap as the virtual XP desktops companies may already be running.

Still, the appeal is there for some customers. Virtualising a Windows 7 migration gives IT a lot more control by keeping the whole process inside the data center and reducing the hardware and support costs as well, Wolf says.

That might make two big migrations more attractive than just one - at least that's what Microsoft, Citrix and a host of third-party developers are hoping, he says.

Microsoft's Dilemma

For its part, Microsoft seems to be playing both sides of the issue. The vendor supports desktop virtualisation but is leery of anything that would threaten the primacy of the stand-alone PC as the main business computing platform.

Even Microsoft's desktop virtualisation product manager doesn't seem comfortable with the idea that most or all of a major company's PCs could be virtualised.

"We expect to see a significant amount of deployment [of virtual desktops] on Windows 7 from CIOs looking for reduced costs in deploying applications on Windows 7," says Scott Woodgate, the director of Windows product management, who is leading the development of Microsoft's desktop virtualisation technology.

While Microsoft is "excited to have an offering" in the virtual desktop market, the company believes customers "should virtualise for the right reasons -- for the flexibility it offers - not just focus on the potential cost savings," Woodgate says.

On the negative side, VDI implementations are more complex to configure than more standard PC-based networks, he contends. VDI networks require administrators to create virtual machines, permissions and policies governing how the VMs behave and the images from which VMs are launched, in addition to configuring and managing a standard PC network.

Some users agree with Woodgate's assessment of the complexity of VDIs. George Thornton, network operations manager for the Montgomery Independent School District in Texas, and Landon Winburn, Citrix administrator for the University of Texas Medical Branch, say that planning virtual desktop rollouts can be intimidating to IT groups that are just getting started.

Figuring out which of several delivery methods will be most effective for specific types of users is difficult, as is creating just a few "golden" operating system images that most users can launch as "their" desktops, rather than trying to keep a different one for each user, Thornton says.

Further, Microsoft's Woodgate worries that companies may overestimate their potential cost savings with virtual desktops because they don't add in the cost of gearing up the data center to support it.

"You're replacing the hard drive of a laptop, which is about the cheapest memory there is, with space in a storage-area network, which is about the most expensive memory there is," Woodgate adds.

Calculating Savings On that point, Woodgate and Winburn disagree. Server- or SAN-based storage is secure, backed-up, cheaper to maintain and far more rarely lost, broken or abused than a laptop hard drive, Winburn says.

And, Thornton says, even looking just at hardware costs, virtual desktops saved his organisation about $100 per machine.

The frugal school district used Citrix's free XenServer virtualisation software on its servers. "With a thin client and Linux OS on it, half a gig of RAM, a little Atom processor, a license for XenDesktop, plus the cost of a server divided by 30 - we figured we could get 30 VMs per server -- we came up with about $550 per unit," Thornton explains.

"Compare that to $650 to $700 for a regular PC. Thin clients have no moving parts. They're built to resist heat," Thornton says. "We figure they'll last eight or 10 years, compared to the three or four Gartner recommends for a PC. That raises the savings even more."

It's not just K-12 education in Texas that's tapping the power of virtualisation. At the University of Texas Medical Branch medical school, the support, hardware and network load are different, depending on what type of virtual desktop is involved, Winburn says. But any kind of virtual desktop delivers a far more efficient use of IT resources than putting all the power of a PC on every user's desk, he explains.

"The big difference is that you don't have to support the endpoint -- just the user settings and the network and servers," Winburn says. "I could put five or six PCs on a T1 at a clinic somewhere, and people are going to complain that Outlook is slow to open or it takes too long for browsing. I could throw 30 or 40 [Citrix thin clients] on that connection sharing one desktop image back in the data centre, and they run like a champ."

Expanding Options

Traditional, terminal-services-based virtual desktops allow dozens or hundreds of end users to sign onto a single operating system and set of applications, all running on a back-end server. That keeps costs very low but limits or eliminates the ability of individual users to configure their own environments. It also keeps them from viewing bandwidth-intensive video, Flash animation or other multimedia, whether on the Web or on controlled internal applications. This happens because most desktop virtualisation software doesn't have a mechanism to support it, Mann says.

That's changing with newer versions of the server software from both Citrix and Wyse Technology. Citrix's recently released XenDesktop 4 supports not only multimedia, but also USB connections at the client side. The result is that end users can plug in peripherals like printers, scanners and memory sticks, or even fans, lights and desktop toys, if they like, Mann says.

VMware, long the leader in the virtual server market, plans to release similar support in its VMware View VDI products early this year.

But even then, it will trail Citrix in the number of delivery methods it offers for virtual desktops and the breadth of products tailored to specific problems. One of the offerings that sets Citrix apart is Citrix Branch Repeater, which slashes the amount of bandwidth required for remote sessions of the notoriously chatty Exchange server, Mann says.

Another is Citrix's HDX technology, which eliminates one of the few barriers to using a virtual PC just like a real one, according to Graves. HDX allows users of VDI-based virtual desktops to run Web-based multimedia and to plug USB devices into their local machines, even if the software operating the peripherals and the browser is running in a data centre somewhere, Graves says.

Still Tactical

Given all the variables that are still in play, there probably won't be an explosion of Windows 7-inspired desktop virtualisation in corporate America anytime soon, says IDC analyst Michael Rose.

Traditional shared-session virtual desktops will remain popular in their usual niches, whether with Windows 7 or other operating systems, Rose says. It will take time, however, even for companies eager to use newer VDI systems, to add the network and server capacity they require.

"It would involve significant spending in the data centre to accommodate adding vast numbers of users on virtual machines," he says. "Desktop virtualisation will continue largely to be a tactical technology, though as it moves more toward the endpoint device - handhelds and other nontraditional hardware -- there's more of a possibility it will become very common."

Bottom line: Windows 7 could be a catalyst for some additional virtualisation, given improvements in the technology that have helped mitigate concerns over performance, lack of personalisation and other issues.

However, this technology isn't seamlessly stitched together yet. Administrators still have to master the nuances and best practices, and few will want to make the transition to virtualisation at the same time they convert to Windows 7.

Kevin Fogarty is a freelance writer covering IT, science and engineering. Contact him at [email protected].

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