Andreas M. Antonopoulos and John Burke

Andreas M. Antonopoulos and John Burke

3/04/2010 @ 6:00PM

A Virtual Desktop Primer

Almost a quarter of the companies we interview are implementing desktop virtualization, at minimum as a pilot project. Desktop virtualization refers to abstracting a desktop workload (operating system and applications) from desktop hardware. Via the network, a Virtual Desktop Infrastructure delivers the user interface (keyboard, video, audio, mouse) to a software- or hardware-thin client. The client does no processing (other than of user-interface events like key-presses or mouse movements) and stores no data locally.

To users, a virtualized desktop ideally seems identical to a conventional one–an operating system with a suite of applications. Because the OS and applications are provisioned and managed centrally, however, the virtual desktop can be locked down tightly, and virtual desktops can always boot off a clean operating system, never acquiring (as Windows systems are wont to do) the dreck that gradually slows their performance. Central IT can upgrade applications and operating systems transparently, in the background.

Organizations deploying desktop virtualization also do so to enable real-time provisioning of new desktops, to reduce management and operational costs, to ensure greater security, and to better manage computing resources. Business continuance and disaster recovery are a big consideration as well, especially for server-centric deployments for financial-services and professional-services firms. Additionally, virtual desktops offer tremendous control and cost savings from standardization. For example, if 100 users can run a substantially identical desktop, a centralized installation (virtual desktops) will be significantly less costly to manage than traditional desktops.

In server-centric desktop virtualization, the desktop runs in a data center while the peripherals (screen, keyboard, mouse, sound) are on the user’s desk. The virtual desktop is basically transmitted across the network in real time. As such, desktop virtualization is sensitive to variations in network latency, packet loss and capacity. As a user interacts with their desktop, a user input such as moving the mouse results in a round trip across the network before the result is seen on the screen. Packet loss or delay in the network will therefore create a discontinuity in the user experience (sluggish mouse, unresponsive windows, delays in clicks).

Desktop virtualization therefore can deliver both extremes of user experience–absurdly fast response because the desktop is running on a very powerful server, or an awfully choppy and discontinuous experience because it is mediated by the network. The difference between these two extremes is dependent on the network. Companies interested in deploying desktop virtualization should carefully assess their networks’ readiness for this technology.

With the above considerations in mind, we can clearly identify cases where desktop virtualization really shines and cases where it will be difficult to implement. The best environments for desktop virtualization are those that combine a consistently fast network with fairly consistent desktop configurations (i.e., the same applications for all users, or a small set of such standard configurations). We see successful deployments primarily in the following environments:

Hospitals. A geographically concentrated user base (campus) and fast local area network (campus optical fiber), hospitals make ideal environments for desktop virtualization. There is a very fast and low latency network between the thin-client desktop and the server where the desktop is running. Desktop configurations are often very standardized with specific applications related to specific job functions. Virtualization also enables “follow-me” sessions, where for example a doctor can access a running virtual desktop from each patient room, office or lab they work from throughout the day.

Universities. Similar to a hospital, a university campus offers a wholly owned optical-fiber backbone that connects the thin client to the data center. High speed and low latency mean a consistent high-quality user experience. The desktop configurations of computer labs and admin offices can be standardized and managed centrally. Virtualization also means that the “lab” is just a room, but the desktops can be accessed from anywhere on campus.

Call centers. Call centers offer a highly concentrated user population with either a single call center application or a few standardized applications. If the back-end servers are in the same building or campus, the network will be consistently fast and reliable.

Developers. Offering extreme performance from a powerful back-end server, virtual desktop make excellent developer desktops. Virtualization also keeps the intellectual property in the data center and allows for rapid deployment of desktops for contract, project or short-term workers.

Conversely, some environments and circumstances make desktop virtualization harder to deploy. A firm with highly specialized-knowledge workers who are also highly mobile might not be a good environment for desktop virtualization. If the users move around, experiencing network connectivity of varying quality and performance, they will also experience highly variable desktop quality. If the “power users” each need to customize their desktops with many different applications, then some of the advantages of standardization and central management will be lost.

Companies should carefully assess the readiness of their network and the suitability of desktop virtualization to their corporate culture, user base and work patterns. When deployed under the right circumstances, desktop virtualization delivers excellent results, bringing tremendous performance to end users and great savings through central management and control to ITand reduced risk through centralization of protected data and improved desktop security.

Andreas M. Antonopoulos is founding partner, and John Burke is principal research analyst of Nemertes Research.

Complete Coverage: Virtualization 2009

See Also:

VMware Arms For Microsoft Battle

Citrix Goes After VMware

VMware: My Own Private Cloud

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