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VDI can offer many benefits, but as with any new technology, a business should perform a careful cost-benefit analysis before deployment.
Virtual desktops provide unique flexibility for users, shed many of the configuration and management issues associated with endpoint PCs, and offer recurring cost models. But virtual desktops also pose new challenges, especially if an organization deploys VDI without reviewing the appropriate use cases.
Organizations should evaluate the following VDI benefits and considerations.
The primary benefit of virtual desktops is endpoint flexibility. The virtual desktop exists as a file running on a remote server. Users can access that file from a wide array of endpoint devices, using a network to connect the server to the endpoint client device. For example, a user can log on from a desktop at work, from a laptop at home, from a tablet at a client's office and so on. Even though IT can deploy many devices, the VM -- the virtual desktop file -- remains the same in order to provide the same UX.
There are typically several different types of virtual desktop images available, but the number of desktop images is extremely limited. VDI enables businesses to create and manage their own desktop images, so the business can create desktops with application sets tailored for certain user types, such as finance, HR, development and more.
2. Resource savings
Since the server handles all of the processing for a virtual desktop, VDI endpoints are little more than I/O devices and can function with far less compute capability than the desktop OS and applications might otherwise require. When it comes to VDI, it's the server -- not the endpoint -- that actually performs the work on a virtual desktop.
3. Simplified management and troubleshooting
Where PCs are often tailored and personalized to suit the tastes and preferences of individual users, virtual desktops benefit from uniformity. This uniformity enables the same virtual desktop file to be replicated ad infinitum to support any number of users.
By employing the same OS, application set and configuration, virtual desktops become fast and simple to learn and troubleshoot. In addition, virtual desktops are generally not persistent and typically do not support personalization, although an organization can implement some limited personalization if it needs to.
Ultimately, the choice of virtual desktops is not an all-or-nothing proposition. Virtual desktops can coexist just fine with traditional local desktop computers. This means that businesses can test virtual desktop technologies and services to find a platform and pricing model that best fits their needs.
Once selected, organizations can adopt virtual desktops as quickly -- or slowly -- as they see fit, enabling current traditional desktops to reach the end of their normal lifecycle before making a decision to implement virtual desktops and other client hardware.
When IT pairs hyper-converged infrastructure (HCI) with VDI, the ease of scalability further increases. HCI systems enable IT to add storage and capacity in conjunction with compute capacity, reducing the risk of I/O bottlenecks.
5. Same image utilization
The real power of a virtual desktop is in its standardization. For example, IT can duplicate and proliferate a single desktop image file -- a VM with an OS and applications -- to dozens, hundreds or even thousands of users, with every class or type of user employing the same desktop image. There may be several different desktop images to choose from, reflecting different classes or types of users, but every user does not get a unique image tailored just for them.
6. Cost savings
Virtual desktops can potentially save money for a business in the choice of endpoint computers. Since the real work of a virtual desktop is being performed on the server, the endpoint is little more than a "dumb" terminal for input, such as a keyboard and mouse, and output, such as the monitor. Ideally, users can access powerful business-class applications using an endpoint that might otherwise lack the capabilities to run those same applications locally.
Thus, virtual desktops can enable a business to purchase simpler and less expensive endpoint computers for users. In addition, an organization can purchase the endpoints in volume, taking advantage of volume discounts. Some organizations even abandon the notion of providing endpoints, enabling employees and other users to BYOD with laptops, mobile devices or tablets. The risk is in servers and connectivity: If users cannot access virtual desktops, productivity ceases, and it's unlikely that basic endpoints would be suited for any practical tasks until IT restores the virtual desktops.
Weighing the VDI option
There are potential limitations involved in adopting virtual desktop technology.
Use cases. Virtual desktops are not for everyone. Virtual desktops are best suited for deploying large volumes of the same desktop. For example, a call center with dozens of employees might be well suited for virtual desktops where every employee would use the identical desktop and applications. Such a deployment would eliminate a great deal of endpoint device maintenance for the business. Similarly, virtual desktops can be handy for temporary use, such as for vendors, business partners and temporary employees, where the business can provide a common desktop experience that users can employ with their own laptop or tablet.
Own or rent. Businesses must decide whether to locally deploy VDI in a data center or subscribe to a desktop as a service (DaaS) cloud service. VDI can be a suitable option when the business must exert direct control over the virtual desktop environment and image files, but the deployment requires an investment in hardware, software and IT expertise. DaaS gives up direct control over the infrastructure and image files but offers simple and convenient virtual desktop access for a relatively low recurring cost.
Server and connectivity risk. Desktop computing is all about employee productivity. When a PC fails, only that PC -- or that employee -- is affected. The move to virtual desktops imposes a significant change to business continuity because many users may be using virtual desktops that exist and run on the same remote server. If the virtual desktop server fails, it affects all virtual desktops on that server, which, in turn, affects many employees.
Similarly, virtual desktops rely on networks such as LANs and the internet to connect virtual desktop servers to endpoints. Any congestion or disruption in network connectivity can potentially affect all virtual desktop users.
Proliferation and licensing. A business that deploys its own VDI will have the option to create and manage virtual desktop images and the ability to create any number of images with application suites tailored for certain user types. But there are two important problems with controlling and managing virtual desktops: proliferation and licensing. IT must manage every virtual desktop with patches and updates. The more different virtual desktop images that a business creates, the more patch/update management it will need. It's a slippery slope that can quickly consume IT time and expertise that the business is trying to save.
Licensing is another problem that can get a business into legal trouble. Every OS and application must be associated with a license from the software maker. Putting an OS and applications into a virtual image and replicating that image countless times for a multitude of users can quickly exhaust the available licenses and accidentally leave the business on the receiving end of a lawsuit.
When businesses use an existing DaaS virtual desktop, they pay for software licenses in the monthly fee. When businesses use VDI, there must be an adequate number of OS and software licenses to cover every virtual instance that they deploy. For example, if the business deploys 20 virtual instances with software X, that business should have at least enough licenses to cover those deployments.