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Hyper-convergence found its first home in many organizations as a good fit to host virtual desktop infrastructure. But just because hyper-converged computing and VDI seem to go hand in hand doesn't mean that you should think of hyper-converged infrastructure as plug and play for VDI use.
The type of workloads the end users place on your VDI will primarily shape your options for an HCI system. The work patterns of those VDI users are also a key factor, as is the software they will run on the virtual desktops.
Determining user requirements
The most basic question you need to answer is how many virtual desktops you need. Most hyper-converged computing systems have a minimum number of nodes in a cluster and can handle hundreds of virtual desktops. If your IT needs aren't at that level yet, implementing HCI would be overprovisioning and needlessly expensive.
Once you know how many machines will be virtually deployed in your VDI, you will need to determine the work patterns of the users of those machines. Typically, VDI users can be put into three groups: task users, knowledge users and power users. Each has different levels of resources they need from the shared pool of an HCI system.
Analyze the user group as a whole to determine the concurrency rate -- how many users are on and working at the same time. Your hyper-converged computing system will need to be able to operate efficiently at the peak demand time. This is usually when end users all log on if they are in the same time zone, an exercise commonly known as a boot storm. Having a geographically dispersed workforce eases resource demand peaks, but you will still need to find out when those peaks occur and provision resources to meet those peaks.
Benefits of HCI for VDI
Cost savings are also one of the draws for HCI among VDI buyers. The main cost savings come in the form of reduced management costs, because the HCI has most of the management functions built in and at least partially automated. That means fewer specialized types of IT administrators, such as storage admins, for most operations that use HCI.
An additional benefit of hyper-converged computing is that it can ease or even eliminate one of the primary problems VDI faces in traditional IT structures, the storage bottleneck. Storage capacity demands grow faster than any other aspect of a VDI system, and traditional storage systems are not as easy to scale as HCI. This can lead to storage becoming the resource that slows the performance of VDI for your end users.
The ease of expansion of resources in an HCI system makes the storage bottleneck all but disappear. Simply adding more nodes to a cluster will add more storage capacity to the virtualized logic pool to be shared among your VDI users.
Drawbacks of HCI in VDI
The ease of expansion can also lead to one of the drawbacks of an HCI implementation. You might overprovision one resource to meet the demands of another. Simply put, since each node contains storage and compute capacity, you may end up with more compute resources than your VDI system needs in order to meet the storage demands.
Vendor lock-in is also a concern if you choose to adopt HCI. Since you will pick the HCI vendor with a product best suited for your VDI needs, you will be committed to buying future technology from that vendor unless you want to do a forklift migration to another platform. If a new technology or feature set comes along that offers better performance, improves efficiency or lowers the cost of hyper-converged computing, you can only take advantage if your vendor offers it.