Developing a proof of concept plan for virtual desktops

Refer to these checklists as part of a proof of concept plan when deploying virtual desktops to ensure that your final objectives are organized and clear.

When designing your virtual desktop environment, proof of concept confirms that moving away from old methods for desktop deployment will save your company time and energy.

Identifying your business's ultimate objective is the first -- and most critical -- aspect of a proof of concept (PoC) plan. Without fully understanding and clarifying your goals, tests will lack direction and lead to inconclusive results. Each criterion for success should be clear and concise so there is no disagreement as to whether the solution meets your business' needs. The success criteria should also be identified at the onset of the PoC, as it could affect the overall architecture.

Your PoC must also identify past challenges and include ways to overcome these challenges. For example, some organizations validate how easily a Windows desktop will be delivered to worldwide users on older hardware, while others focus on how they will update applications more frequently and easily.

As you move through the planning process and understand all of your goals, you should verify when all pieces will be ready. Consider using a checklist such as the following example:

Item Completed Notes
Success criteria defined - Success criteria should be specific, measurable, achievable, realistic and timely.
Success criteria approved by stakeholders and project sponsors - It is important to have a signed statement as to the agreement of the success criteria. As time passes, the criterion has a tendency to fluctuate and increase the difficulty in determining success.
People available - To implement a virtual desktop architecture in a test environment, different groups of individuals -- desktop operations managers, network managers, application managers and Active Directory managers -- are needed to understand the components and potential integration opportunities.
Equipment received - Without the correct hardware, the PoC won't be able to validate the design. Before the PoC can begin, all hardware must be ready. This includes desktop appliances, hypervisor servers, storage, etc.
Software aquired - Without the proper software, the PoC cannot begin. Work with your preferred vendor to get this in place.
Licenses acquired - To complete the PoC, software licenses are required. It is recommended that you have a partner involved who can identify and provide the required license number in time to start the PoC.

The next step in creating your PoC is to outline critical success factors based on user experience, supportability and technical components. In the past, I've used the following matrix to determine critical success factors for users:

Category Criticality Criteria
Graphics High While working with two-dimensional graphics applications, users should experience smooth and responsive functionality within the application on LAN and WAN.
USB storage High Users should be able to access USB storage devices from within their virtual desktop without having to log off or log on.
Printers High Users should be able to print to their local printers from within their virtual desktop.
Visual High Users should have the ability to control screen resolution and modify screen size for their virtual desktop.
User roaming High Users should have the ability to control screen resolution and modify screen size for their virtual desktop.
Personalization High Users should be able to personalize their virtual desktop environment with application configurations, environment settings and user preferences. These personalization settings should follow the user from system-to-system.
Remote access High Users should be able to access a virtual desktop securely and remotely without relying on a VPN client on the endpoint.
Application delivery High Users should only see the applications they have been assigned.
Multi-monitor support Medium Users should be able to seamlessly span the virtual desktop across multiple monitors without the need for special endpoint configurations.
Video Medium Users should be able to view and listen to video and audio content with no significant delays, freezing or pixilation when playing Windows media via LAN or WAN.
Flash Low Users should be able to view and listen to video and audio content with no significant delays, freezing or pixilation when viewing Adobe Flash media via LAN or WAN.

When implementing virtual desktops, users should have the same functionality that they're accustomed to on their physical workstation. Functionality, like graphical update speed, video playback and desktop customizations (if necessary) must be part of the solution and should perform in many different types of environments, such as devices, networks, locations, etc.

From a supportability perspective, I use the following matrix:

Category Criticality Criteria
Redundancy High Users should be able to continue working within their virtual desktop, even if there is a failed component within the environment.
Storage requirements High Storage requirements should be kept to a minimum by regulating a single or small number of virtual desktop images.
Desktop allocation High Adding new virtual desktops into the environment should happen in a matter of minutes while using a single console.
Patch management High Updating the OS with the latest security patches should only be required on a single image or small number of images. Those changes should be propagated to all users' virtual desktops without needing to touch each virtual desktop.

An important factor with virtual desktop software and its viability for rollout comes down to how easy it is to support the environment. Most enterprises contain more workstations than servers. When virtualizing and moving the desktops into the data center, administrators must manage those desktops as well as the virtual desktop infrastructure. Items like patch management and storage requirements, for example, must be assessed.

From a technical standpoint, your virtual desktop solution must be able to deliver virtual desktops to any number of endpoints. This is especially critical if you want to allow employees working from home or other remote locations to securely access virtual desktops.

The two main components of the technical criteria are as follows:

Category Criticality Criteria
Endpoints High The solution must be able to support multiple types of endpoints that users have in the office and at home, including Windows XP and Linux.
Hypervisor High The solution must be open -- allowing it to function with VMware VI3 and Citrix XenServer.

If you're experiencing problems supporting virtual desktops or the infrastructure during PoC, those issues will increase exponentially in a production environment if they remain unresolved. The challenges will be both small and large, but a methodical approach to your PoC plan will make any problem solvable.

Michael Keen is a Senior Solutions Architect with Alliance Technologies in Des Moines, Iowa. He has over eleven years of experience in large-scale application delivery and virtualization projects and has architected and implemented some of the largest Citrix infrastructures in the country using four design principles of standardization, simplification, integration, and modularity. He also brings extensive experience in converging business and IT using Enterprise Architecture and IT governance.

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