To VDI or Not to VDI?

To borrow from Shakespeare, many companies find themselves asking “to VDI or not to VDI?” The first step to determine if Virtual Desktop Infrastructure (VDI) is the right solution for your company is to identify exactly what VDI means for your organization.

VDI actually encompasses several types of delivery, but it is most commonly associated with what Gartner classifies as hosted virtual desktops (HVDs). VDI can also include implementations of server-based computing (SBC), hosted shared desktops (HSDs and client-side virtualization. For the sake of simplicity, we will focus on the hosted virtual desktop model for VDI, since that is the most common assumption of a VDI deployment.

As a virtualization architect, I have been involved in numerous VDI implementations ranging from proof-of-concept projects to full production lifecycles. In the process of design and implementation engagements, one thing is clear: a well-defined list of use-case scenarios is paramount when choosing the proper solution. Some organizations may want VDI but don’t need it, others may need it but don’t understand it, and some may not know what they need. The question becomes how to determine if VDI is right for you — or not.

Understanding What VDI Is and What It Isn’t

VDI stands for Virtual Desktop Infrastructure, but that is not limited to simply delivering a desktop operating system. The OS is just one layer of the Hosted Virtual Desktop model. This model includes the infrastructure layer (storage, network and hypervisor), interface layer (base operating system, locally installed applications and virtual applications), workspace management layer (user data and profiles), delivery layer (remote access and connection brokering) and the client device layer.

However, VDI is not easy to quantify. VDI is not inexpensive, simple, or a one-size-fits-all solution. Granted, it does not have to be overly complex or pricey, but quite frankly, VDI is not for the faint of heart.

Is VDI Right for You?

To determine if VDI is right for you, consider your use-case scenarios. What are you trying to achieve? What are your primary objectives? What applications are you trying to deliver? What do your users need to do?

When answering these questions, create your scenarios. Rarely will you have only a single use-case, but to succeed, you need to limit your use-cases as much as possible.

Use-cases tend to mirror business units or types of users. In an academic setting, this might be split between students, faculty and administrative staff. In a medical environment, your cases might be split by departments (emergency, registration, transitional care, etc.) or general function (patient care, administrative services, etc.).

Regardless of how you define your use-cases, it is important to understand that they must be clearly defined, and they must identify common applications and user functions.

Once your use-cases are defined, you can determine which applications and toolsets are necessary. This is critical to determine if you need to invest in a traditional management of fat clients, a shared hosted solution (traditional SBC) or a hosted virtual desktop (HVD).

Technical factors around any decision include application compatibility, performance, management, scalability, storage and costs. Other factors for consideration are reliability, recoverability, flexibility, ease of use and security.

In the end, any technology solution should be there to support the business, not for the business to support technology. When analyzing if VDI is right for you, understand what roles traditional client computing as well as SBC fulfill, as either of these could be the right solution.

Making the Case for VDI

Defining and refining your use-case scenarios is as much art as science, since there is no clearly defined rule. Some organizations will use VDI regardless of cost or complexity. Others may avoid it outright, even if it is the proper solution. Consider the following when determining if VDI is right for you.

Last year, Gartner rated hosted virtual desktops in the adolescent maturity range with a high benefit rating. VDI is cutting-edge, but really shines when your issues revolve around application compatibility, peripheral support or resource isolation. A more traditional SBC model may be more appropriate if you need shared resources for increased scalability or a more mature and proven technology.

Following are six real-world scenarios which may help you understand when VDI fits and when it does not.

  • VDI for Application Compatibility. A client in the credit industry was migrating to a centralized data center model and leveraging thin clients for data-entry. This initiative was started in order to better manage access to their data as well as provide more flexibility to their workforce. However, their primary billing and collection customer service application was only supported on Windows XP. In order to meet both requirements, a VDI solution was deemed necessary.
  • VDI for Peripheral Support. A client in the medical industry was already using thin clients to deliver hosted applications (SBC) from within their data center. However, as part of a green initiative, they were attempting to move away from developed x-rays and migrate into digital radiography. This required enhanced USB support for the image capture as well as the 32-bit graphics of Windows 7 to get the proper resolution.
  • VDI for Resource Isolation. Another client in the landscaping industry was facing a different issue. Their applications were fully compatible with their existing application hosting model (SBC). However, whenever the route planners were using the geographical information software to plot the drivers’ routes, the server’s resources would become consumed. This would cause other users’ performance on the same server to suffer. By moving the geographical and routing software packages into a VDI scenario, the customer was able to dedicate and isolate resources, preventing the collateral effects.
  • SBC for Scalability. A customer in the insurance industry was designing a new “Bring Your Own Computer” (BYOC) initiative. Due to strong central management and well-defined use-cases, they decided everything could run on a hosted shared desktop model. This would allow them greater user density by sharing resources among multiple users.
  • SBC for Maturity. An application development firm specializing in healthcare software needed a mature product for delivering their application to subscribers in the home-health field. This software platform required nationwide remote access to applications relying on a central database. Due to the nature of the application and users, this system needed to be built on a scalable and mature product set using server-based computing for the hosted application.
  • SBC as a Proven Technology. A food-services industry customer was considering a secure computing environment for offshore contractors. Neither SBC nor VDI could deliver the necessary applications and performance. However, this client decided to focus on server-hosted applications, because this was a proven technology with a strong support base and broader support options.

In Conclusion

The ultimate decision to implement VDI will vary for each customer and each use-case scenario. I recently spoke to Daniel Feller, lead architect of worldwide consulting solutions at Citrix Systems, who provided further support for this point.

“There is no right or wrong answer when deciding between a VDI or SBC solution as both work in almost any use-case,” he said. “In fact, after looking at the technical criteria and value of each option, the final decision often comes down to comfort and familiarity. If an organization already has an SBC environment, they will more than likely continue down that path while organizations with a strong desktop management team will often opt for VDI.”

Like any IT project, the keys are understanding where the technology fits within your organizational needs, Daniel pointed out. It is just as important to understand the risks imposed by the technological solution. VDI is not for everyone, and those organizations that implement VDI usually implement a hybrid solution — using VDI where appropriate and leveraging SBC to augment their offerings.

Andy Paul

Andy Paul is a principal consultant at GlassHouse Technologies.

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