Critical Testing Criteria: Virtual Desktop Infrastructure

VMware, Microsoft, Citrix and others have forged ahead in making virtual desktop infrastructure a viable choice for centrally managed, highly configurable use cases. Here are "three C's" to consider when testing a virtual desktop product: components, capacity, capability. Components include both the services and underlying physical components, capacity is the number of virtual desktop instances that can be supported by your host systems and capability now includes feature-rich graphics and peripheral device support along with the usual desktop and line-of-business applications.

1. License costs
In addition to the "three C's" one of the most important testing criteria is licensing costs. None of the competing vendors make it easy to do an apples-to-apples comparison, so you'll need to do some noodling to get a price per-desktop, per-year figure. It makes a difference how many years you include in your calculations. I suggest looking at a minimum of three and a maximum of five years, depending on your current physical desktop or laptop formula. Speaking of physical systems, you should factor in the costs of the user devices on which the remote virtual desktops will be hosted.
2. Hypervisor platform
Ensure that the data center software, including the server operating systems and hypervisor platform, are the right version to handle the virtual desktop load that you intend to run. For example, the latest crop of remote virtual desktop products is now capable of handling full-motion video, multiple monitors and other advanced display and peripheral device features, but only if the underlying virtualization platform is also of the latest vintage. It's worth noting that you should now add a professional-class graphics card to your technical checklist if advanced workstation graphics are in your virtual desktop future.
3. Connection broker
VMware introduced PCoIP (PC over IP), and Microsoft is coming out with RemoteFX to enable an enhanced user experience, which means the connection broker must be tested to ensure it supports these latest-and-greatest technologies. If you use a third-party connection broker (likely in multivendor VDI environments) it's worth checking to ensure that optional agents used by the connection broker don't conflict with agents that might be needed on the virtual machines. It's also worth seeing if the agents provide enough overlap that you could eliminate one for possible cost/complexity savings.
4. Application streaming
Remoting a virtual desktop is usually just half the battle for most desktop administrators. Users must have applications, and there are a number of application delivery products that can be used to provide this service. Ensure that you test interoperability between the candidate virtual desktop product and your application streaming choices. While you may single-source the virtual desktop and application delivery, it's still worth testing how the products interoperate in your environment.
5. Directory services
This is pretty simple. Make sure your current directory infrastructure can provide the information needed by the virtual desktop product. Because the virtual desktop, connection broker, application streaming tool and a number of other components may be using the directory service to properly provision users ensuring that your directory service will work correctly with this components is essential to a successful deployment.
6. Agents
It's common for at least one component in a virtual desktop implementation to use an agent on the virtual desktop to keep track of what's happening. You should test these agents to ensure they are able to report characteristics such as virtual machine uptime, activity status, performance counters, licensing information and application usage.
7. Offline operation
Some virtual desktop products allow users to work offline, such as on an airplane or in a remote office where network connectivity may be unreliable. If this is a use case that your organization wants to support, then add offline operation to your checklist. Look at how offline changes are reconciled to the server-side virtual desktop instance. See how well the virtual desktop performs when it is disconnected for several days or a week, if this is a circumstance your users might encounter.
8. Secure access
Virtual desktop implementations are trying to provide desktop resources to authorized users. Your organization gets to make choices about how strict the authorization process should be and how security surrounding the virtual desktop will be deployed. There are a lot of fast-moving parts that must work in close concert with each other in a virtual desktop environment, so it's critical to test and understand how the security offerings in your candidate VDI tools measure up in your environment.
9. Physical connectivity
Even with advances in offline operation, it's worth auditing your underlying physical network for reliable connectivity between the users and the data center that will host the virtual desktops. Look for firewall, load balancing, acceleration, deduplication and other special purpose network devices that might be placed between your users and the hosted virtual desktop to ensure that the VDI tools you select will work in your network.