The set of virtual desktop system enhancements Citrix Systems announced this week is unusual not for its timing or technical acumen, but for focusing on the experience of actual end users. Analysts say that IT knows the user experience with desktop virtualization is absolutely critical to success.

"We did a study that came out just before VMworld [in August] that showed the quality of the user experience is the top criterion enterprises use to evaluate virtual desktop infrastructures," says Andi Mann, head of systems and storage-management research at Enterprise Management Associates.

Asked to rate the most important factor in choosing a desktop virtualization system, out of 10 options, 75 percent of companies chose "Ease of use for end-users."

"The end user experience is critical, and there are some really clever things in what Citrix is doing address that -- multiple ways to deploy desktop services and to improve performance enough to fundamentally improve what the users are actually doing," Mann says.

Citrix's New Improvements for End Users

The improvements - in load-balancing at the server, support for graphics and peripherals at the client, and an additional way to virtualise a desktop application - come free for customers with existing enterprise license or automatic-upgrade contracts.

The most notable new feature in XenApp 5 Feature Pack 2, which is free to customers with enterprise licences and upgrade-by-subscription plans, is VM Hosted Apps. The feature allows Citrix customers to run desktop applications on a separate virtual machine that runs on a physical host running XenServer.

Most desktop applications running under XenApps run in parallel on a Windows or Xen server. XenApps clients connect by logging in to the server and using software already running on it.

With Dynamic Application Delivery, a single application or a specific user's whole suite of applications run on a VM without having to share resources, and without having any difficulty identifying the hardware or operating system on which they run, according to Alicia Rey, product marketing manager for XenApp.

"That's actually a big deal because there are a small percentage of applications, maybe only five to ten percent, that you wouldn't even think to run on XenApps," says Ben Kohn, senior systems architect for Independent Bank, an Ionia, Mich.-based bank with 1,200 employees, 90 percent of whom are connected via Citrix virtual desktops, accessing software running mostly on VMware servers.

"Adobe Acrobat, for example, installs a service that checks on the hardware you're running it on so you don't move it around to different machines," Kohn says. "You couldn't put it on Citrix server or do app streaming with it, but you could install it on a VM and deliver it that way and still use exactly the same infrastructure you would for any other app."

A second feature, HDX MediaStream for Flash, is designed to make graphics-intensive applications run faster by using, where possible, the memory, CPU cycles and graphics card on the end-user's computer in addition to those on the server, Rey says. Currently XenApps only presents an image of what's going on at the server--which Kohn calls the "equivalent of a really long video cable."

Adding a layer of intelligence to the client software to enable it to check for and use local graphics resources takes some load off the server and, more importantly, makes the application appear to the end user to be running faster, Mann says.

Rey says traditional Terminal Services-based Citrix connections are still more secure and cost-effective, but that VM-based VDI gives users the chance to also virtualize resource-intensive applications, or legacy software that doesn't run well in a communal environment.

Mixed Vendor Environments The Norm

That is the second big hit of this round of improvements, Mann says. There are few consistent trends in desktop virtualization except that widespread acceptance of it is at least three years later than user surveys predicted and that organizations that have implemented it have done so in many ways.

"Enterprises tend to deploy between four or five different endpoint virtualisation technologies on average, and almost a quarter deploy more than six different technologies simultaneously," Mann says. "End-user companies are adopting multiple technologies, so vendors interested in that market have to provide integration between them."

The two leading approaches (with a penetration of 70 percent each) are to run applications on a server and let users access them through a Web browser, and the more traditional Virtual Desktop Infrastructure, in which users access full desktop functions on a server using Terminal Services or accessing a VM on a shared server, Mann's study shows.

Despite the variety of implementations, 100 percent of the companies EMA surveyed reported some positive outcome from virtualised desktops. Almost 75 percent reported measureable cost reductions and more than half reported functional benefits such as improving staff mobility or flexibility, security, or business continuity plans.

One Bank's Desktop Virtualisation Strategy for Success

The XenApp 5 Feature Pack 2 also includes power and capacity management features that are designed to allow IT to create rules describing when and how to add or delete virtual machines to keep the servers running efficiently. A capacity planning feature is designed to let IT managers not only estimate capacity demands for certain situations, but also run simulations of each setup through tests to see if capacity plans will break.

"Right now if we have a spike in demand for a particular app, our provisioning services will spin up more VMs to account for it and that would only take about 15 or 20 minutes. But it's 15 or 20 minutes after everybody [end users] have started to feel the pain," Kohn says. "That's a gap that we really appreciate they're trying to fill, to adjust capacity automatically."

Independent Bank has been hurt less than most other banks by the 12-month economic downturn, but it has been tightening its belt and only spending money on technology where it can significantly improve efficiency and stability, according to Peter Graves, the company CIO.

This year that's included spending "a couple of million, all told," on a new storage area network, disaster-recovery strategy, DR site and appliances that could have the bank back online in hours rather than days, and upgrades to its 10-year-old Citrix network.

"It takes so many of our resources to maintain our network that we would like to be able to divert some of those resources to other things by making the infrastructure more efficient," Graves says.

MediaStream for Flash could significantly pare back the $400,000 or so the bank spends to refresh desktop hardware every year. Rather than replace old PCs that act as thin clients, the feature may allow the bank to leave those machines in place and make use of memory and CPU capacity that have been wasted until now, Graves says.

The Competition with VMware, Microsoft

Features like that--as well as XenApps' continuing superiority over VMware's desktop virtualization technology in a feature called context switching that is used heavily by servers supporting VDI, but less so by those running server-based applications--will probably keep Citrix ahead of its competitors both in the market and at Independent Bank, Kohn says.

"We tested them head to head and Citrix, which is optimized for context switching, had something like a 25 percent advantage over VMware," Kohn says. "ESX performs so well on the server side, though, that we're pretty entrenched there. There are a lot of features in disaster recovery and management and business continuity planning that Citrix is still catching up on."

That may be clear for Kohn and Graves, but most of the rest of the market will be roiled by efforts by Microsoft, VMware, Citrix and a steadily growing number of competitors hoping desktop virtualization is finally ready to become a market-dominating reality, Mann says.

"VMware is doing some great things under the covers and with partnerships and other areas, but they don't have the variety of delivery mechanisms that Citrix has, or the focus on enhancing the endpoint, which is a real advantage," Mann says. "Things like the policy based load balancing, some very large, mature customers of Citrix will love; mostly, I suspect, that's not as important as having more ways to deliver apps to the user and deliver a better user experience."