Microsoft has several virtual technologies that can ease desktop management -- you can use RemoteApp, deploy terminal...
sessions or create a virtual desktop infrastructure (VDI).
But which of these methods should are right for you? There is no clear-cut answer. Since all three technologies have their own advantages and disadvantages, you need to determine which one best suits your organization's needs.
The pros and cons of Terminal Services (Remote Desktop Services)
In a Terminal Services environment, every desktop PC is treated like a thin client. The client computer connects to a terminal server, which runs the user's operating system (OS) and applications.
From a desktop management standpoint, Terminal Services -- which was renamed Remote Desktop Services in Windows Server 2008 R2 -- is a middle-of-the-road solution. Although the OS and applications are centrally located and thus easier to manage, Terminal Services sessions can be very resource-intensive and require some fairly beefy hardware. In addition, certain applications do not function correctly in Terminal Services. Therefore, test your entire application set before implementing Terminal Services/RDS.
The pros and cons of RemoteApp
RemoteApp is a Terminal Services feature that was introduced in Windows Server 2008. It is a good option if you want centralized control over your applications, but you don't want a full-blown Terminal Services environment.
With RemoteApp, the terminal server hosts individual applications instead of entire desktop sessions. As a result, users can continue using their existing Windows desktops. While the user's applications actually run on the terminal server, they provide the illusion of running locally.
The main advantage of RemoteApp is that it provides centralized application management. Furthermore, since Terminal Services only hosts applications and not entire desktop sessions, RemoteApp is not as resource-intensive as a normal Terminal Services environment.
The pros and cons of VDI
Microsoft's VDI technology is an extension of Remote Desktop Services in Windows Server 2008 R2. Like in a normal Terminal Services environment, a user's desktop and applications are hosted on a network server. However, the similarities between Terminal Services and VDI end there.
VDI involves virtualized computers that are hosted on a Hyper-V server. Remote Desktop Services is required if you want to deploy VDI, but its only task is to facilitate the connection between the user and the virtual desktop. In other words, Remote Desktop Services manages user sessions, but it does not directly host virtual desktops.
There are several potential benefits to a VDI deployment. VDI offers much more flexibility than Terminal Services, and application compatibility is less of an issue with VDI than with Terminal Services and RemoteApp because VDI deployments use true desktop OSes.
Another advantage of VDI is that the operating system and applications can be centrally managed. Best of all, when a user logs off, his virtual workstation is reset to a pristine state. (That is, unless you deploy personal virtual desktops, which allow users to have their own virtual desktops that they can personalize).
However, there are disadvantages to VDI. The technology usually requires several servers and is expensive and complicated to deploy. Furthermore, Windows Server 2008 R2 does not provide full fault-tolerant solutions for VDI deployments, so system failures could be an issue.
Which Microsoft technology should you use?
The technology that is best for you depends on your organization. Here are some factors to consider:
- RemoteApp is the least expensive of the three methods, and it's the least complicated one to deploy and maintain. If a failure occurs, users only lose access to the applications that are hosted. The OS will still work, as will any applications installed locally on the desktop (such as Internet Explorer). However, while RemoteApp eases application management, it doesn't address desktop management.
- Although Terminal Services is more complex and expensive than RemoteApp, it is still relatively easy to deploy and maintain. However, application compatibility can be a problem. Furthermore, if a failure occurs, users may be unable to work until the failure is resolved because their entire desktop OS is hosted on the terminal server.
- A virtual desktop infrastructure is much more expensive and complicated to deploy than Terminal Services or RemoteApp, but it provides the highest degree of flexibility. However, as with Terminal Services, a failure could severely interrupt workflow because users' desktop OSes are hosted on a network server.
If your goal is to gain better control over application management, then RemoteApp may be the technology for you. On the other hand, VDI is the better method if you want a comprehensive desktop management technology.
ABOUT THE AUTHOR
Brien M. Posey, MCSE, has received Microsoft's Most Valuable Professional Award four times for his work with Windows Server, IIS and Exchange Server. He has served as CIO for a nationwide chain of hospitals and health care facilities and was once a network administrator for Fort Knox. You can visit his personal website at www.brienposey.com.