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All types of virtualization have at least one thing in common: The abstraction of something physical into discrete parts via software. Today's data centers sport many different types of virtualization beyond the familiar server virt.
In fact, server virtualization has been around for so long that most IT administrators don't need a primer -- it uses a hypervisor to divide a physical server into VMs, the benefits of which include having less hardware to buy and manage, more efficient resource usage and improved resilience.
But what about the other types of virtualization admins run into these days? It's time to get this straight.
Network virtualization takes the available resources on a network and breaks the bandwidth into discrete channels. Admins can secure each channel separately, and they can assign and reassign channels to specific devices in real time. The promise of network virtualization is to improve networks' speed, availability and security, and it's particularly useful for networks that must support unpredictable usage bursts.
For IT admins, network virtualization can lighten the load associated with network management because many tasks -- such as configuration and device discovery -- are automated. Additionally, admins can centrally manage files, add or reassign storage media, and share or reallocate storage space among servers as needed.
Storage virtualization uses software to find physical storage space from multiple devices and pool it into what appears to be a single storage device that machines can use. The software receives I/O requests from physical devices and VMs, then sends the requests to the location of the physical storage that's part of the overall storage pool. Admins can manage pooled storage from a central console.
Hyper-converged infrastructure and other modern approaches to virtualizing the data center use storage virtualization in conjunction with other virtualized resources, such as network capacity and compute. The benefits of storage virtualization include simplified management of heterogeneous storage types, reduced hardware costs and increased performance and reliability.
With desktop virtualization, the goal is to isolate a desktop OS from the endpoint that employees use to access it. But there are many different types of desktop virtualization.
It's also important to remember that desktop virtualization and virtual desktop infrastructure (VDI) aren't the same thing. VDI uses host-based VMs to deliver virtual desktops, but desktop virtualization methods, such as the shared host model, host-based physical machines and client virtualization aren't VDI.
With host-based desktop virtualization or VDI, workers connect to a virtual desktop over a network using a remote display protocol. The clients can be traditional desktop PCs, thin clients, zero clients or even mobile devices, such as smartphones or tablets. One user connects to one VM that runs the OS and applications he or she needs.
When multiple users connect to a shared desktop, as is the case with Microsoft Remote Desktop Services, it's known as shared hosted desktop virtualization. And if the only thing users must access from this shared desktop is a single application, then it would be called application virtualization.
With application virtualization, an app runs separately from the device that accesses it. Application virtualization makes it possible for IT admins to install, patch and update only one version of an app rather than performing the same management tasks multiple times.
The most common approach to application virtualization is the server-based approach where the application runs in a VM -- either in the data center or another hosting service -- and users interact with the application over a remote display protocol. The line between desktop and application virtualization is somewhat blurry. An application can't run independently of an OS, so in a way, application virtualization is desktop virtualization. Often, the use case dictates which term is correct.