When an organization begins transitioning to VDI, several decisions need to be made. One such decision is whether
users should access VDI sessions through dedicated thin client hardware, or PCs running thin client software. Since there are compelling arguments on both sides, I wanted to take the opportunity to present the pros and cons of using thin and thick clients.
One of the primary benefits to using thin client hardware is security. Thin client devices almost always lack an internal hard drive and removable media ports, which means thin clients disable users from copying data in the network to removable media. Likewise, users are also unable to install unauthorized software. Because thin client machines typically do not have a hard drive, there is little to no risk of viral infections.
Although a desktop PC can be used as a thin client, the thin client software typically resides on top of a normal operating system (OS). As such, it would be susceptible to many of the same types of security risks as it would be if it were operating as a regular PC.
Initial deployment costs also need to be considered. While it is true that, typically, thin client hardware has a very low price tag, the cost of deploying thin clients may be much higher than that of using PCs -- if you already own PCs that can be reused. Of course, if you are starting from scratch, using thin client hardware is most likely going to cost a lot less than using PCs. Some thin client devices sell for as little as $200.
Software licensing costs
Thin client hardware is usually less expensive in terms of software licensing costs because a desktop PC acting as a thin client runs thin client software on top of a traditional OS. This means you may be required to license two separate OSes for each PC: the OS running locally on the PC's hard drive, and the OS running in the VDI environment. On top of that, there may be licensing costs associated with the thin client software running on the PCs.
You could also use a stripped down operating system, such as Windows ThinPC, to turn an old PC into a thin client, which requires Software Assurance.
One of the big selling points behind thin client hardware is that using such devices reduces maintenance costs. In some ways this is true, but it's possible that you might spend less with PCs. Let me explain.
Thin client devices are essentially proprietary PCs that have been stripped bare. As such, there really isn't much maintenance associated with a thin client device. There are no moving parts, with the possible exception of a fan, so thin client devices tend to last a long time. However, when a problem does occur, there might be nothing you can do to fix it -- you may be forced to simply replace the device. But keep in mind that when a PC has problems, you can usually replace the failed component for much less than the cost of replacing a thin client device.
Of course, this is only taking hardware maintenance into account. PCs need constant maintenance at the software level. For example, the OS must be patched on a regular basis, and the antivirus software must also be kept up to date.
Another advantage to using thin client devices is that they tend to consume much less power than PCs. Power consumption varies among makes and models, but some estimates indicate that thin client devices only consume about one-seventh the power that a PC does.
It's clear that thin client devices tend to have more advantages than PCs in most situations. It may be valuable to use PCs if you already have them on hand, or if you need additional flexibility that you just can't get with a thin client device.
For example, I recently heard of one organization that went through a corporate buyout. It already had a VDI solution in place, but the company that acquired the organization used mainframes. Because some users had to connect to both the VDI environment and the mainframe, it was necessary to replace the existing thin client hardware with PCs. The PCs network card was linked to the VDI environment, and a secondary network card was linked to a mainframe Gateway. Users ran a dual monitor configuration -- one screen displayed the VDI session while the other screen displayed the mainframe session. Achieving this type of functionality and this level of flexibility isn't possible without dedicated thin client hardware.
ABOUT THE AUTHOR:
Brien M. Posey, MCSE, is a Microsoft Most Valuable Professional for his work with Windows 2000 Server and IIS. He has served as CIO for a nationwide chain of hospitals and was once in charge of IT security for Fort Knox. As a freelance technical writer, he has written for Microsoft, TechTarget, CNET, ZDNet, MSD2D, Relevant Technologies and other technology companies.