Tomasz Zajda - Fotolia
Now that VDI technology is starting to mature, there seems to be a renewed interest in the technology. Like any technology, however, VDI is better suited to some use cases than others. This article examines some top VDI use cases.
1. Bring your own device
Bring your own device (BYOD) might be the single greatest use case for VDI. The basic premise of BYOD is that users are able to work from the device of their choice. While this might initially sound promising, BYOD does present some challenges.
One major challenge of BYOD is inconsistency. End users will likely have completely different experiences depending on the type of device they use. These inconsistencies might not be a major problem if devices are used solely for accessing Web-based applications, but standard desktop applications can be highly problematic.
Most mobile devices are incapable of natively running Windows desktop applications. While it is true that mobile versions exist for some applications, there are almost always platform-specific differences in such apps. For example, Microsoft Office documents sometimes display differently on an iPad than they do on a Windows desktop. Furthermore, the use of platform-specific mobile apps greatly increases the administrative overhead involved in application management.
VDI has proven to be an effective tool for addressing these challenges. Rather than attempting to perform device-level management, administrators can instead focus their attention on one or more pools of virtual desktops. These virtual desktops can be accessed by any authorized device containing a VDI client app (or in some cases, a compatible Web browser). In doing so, users are able to work with a consistent set of applications regardless of the type of device they are using.
In this type of situation, administrators must benchmark the I/O load that is created by each application. The fact that the application is running on a virtual desktop rather than a client device means that the VDI hardware must be able to keep pace with the application-level I/O demand. Administrators should be especially attentive to the additional load that might be created in the future by adding user sessions, new applications or new versions of existing applications.
2. Offline access
Today many VDI environments center around mobility, especially with regard to BYOD. It is important to understand, however, that some users may need to work at times during which no connectivity is available. For example, a user may wish to get work done while on a flight.
Typically, VDI cannot work without connectivity. But there are a couple of options. For example, VMware offers a VDI platform that allows a user to download a virtual desktop and use it while working offline.
Another option is to use Windows To Go. Windows To Go is not technically a VDI solution. Instead, it is a Windows 8 feature that allows a fully provisioned corporate desktop (with applications) to be copied to a USB flash drive. Laptop users can insert the flash drive and boot their computer from it, thereby allowing them to work from a corporate desktop rather than their own personal operating system. This approach works really well in environments in which the user's personal computer is not trusted because it provides the user with a secure, sandboxed environment. Best of all, Windows To Go works regardless of whether or not there's connectivity to the corporate network.
The nice thing about these approaches is that they do not typically produce a significant I/O load on the server because the virtual desktops are being used while the client device is in a disconnected state.
3. High-security environments
VDI is also very well-suited to high-security environments. Some vertical industries, such as banking or the military, need to maintain absolute control over user desktops to prevent the introduction of unauthorized software.
VDI is a good fit for these types of environments because most VDI solutions can be configured in a way that guarantees that corporate desktops will not be modified by the end user. In a Windows Server VDI environment, for example, a connection broker assigns a random virtual desktop to each user's session request. At the conclusion of the user's session, the virtual desktop is reset to a pristine state.
From a storage standpoint, it is important to understand that this approach to virtual desktops results in a slight performance hit. The ability to reset virtual desktops at the end of a session is based on the use of differencing disk snapshots. The parent/child relationship used by the differencing disks results in additional storage overhead, especially for read operations. It is important to benchmark virtual desktop read/write performance prior to rolling out a full-blown production VDI deployment.
4. Heavily regulated organizations
VDI is also ideal for use within heavily regulated organizations. Healthcare providers, for example, must adhere to an entire laundry list of security requirements mandated by the Department of Health and Human Services. If an audit reveals security deficiencies on desktops that handle electronic health records or other sensitive data, the organization can be subject to a hefty fine.
VDI gives the organization centralized control over the desktop operating system. Virtual desktops are generally produced by cloning an operating system image that has been configured to adhere to the organization's requirements. A heavily regulated organization can also use thin-client devices as a way of ensuring that no security deficiencies exist at the endpoint.
As administrators work to create a virtual desktop image, it is important to look for ways to reduce storage I/O. One way of doing so is to remove any unnecessary application components, operating system services and system drivers.
5. Environments with a large user base
Finally, VDI tends to work well in organizations that have a really large user base. When properly configured, VDI can decrease the administrative overhead involved in desktop maintenance by centralizing the administrative process. This can go a long way toward reducing administrative costs.
Although virtual desktops might not be an ideal solution for smaller environments, they tend to work really well in large environments. This is especially true if the organization is regulated or has heavy security requirements. VDI also tends to work well in organizations with well-established BYOD programs.
Keep VDI in mind when you implement a BYOD policy
Evaluate VDI options for storage