What is Virtualization?
In computing, virtualization means to create a virtual version of a device or resource, such as a server, storage device, network or even an operating system where the framework divides the resource into one or more execution environments. Even something as simple as partitioning a hard drive is considered virtualization because you take one drive and partition it to create two separate hard drives. Devices, applications and human users are able to interact with the virtual resource as if it were a real single logical resource. The term virtualization has become somewhat of a buzzword, and as a result the term is now associated with a number of computing technologies including the following:
Server Virtualization
The partitioning of a physical server into smaller virtual servers. In server virtualization the resources of the server itself are hidden, or masked, from users, and software is used to divide the physical server into multiple virtual environments, called virtual or private servers. One common usage of this technology is in Web servers. Virtual Web servers are a very popular way of providing low-cost web hosting services. Instead of requiring a separate computer for each server, dozens of virtual servers can co-reside on the same computer. There are several ways to create a virtual server, with the most common being; virtual machine, operating system-level virtualization, and paravirtual machine.
Storage Virtualization
Storage virtualization is the amalgamation of multiple network storage devices into what appears to be a single storage unit. Storage virtualization is often used in SAN (storage area network), a high-speed subnetwork of shared storage devices, and makes tasks such as archiving, back-up, and recovery easier and faster. Storage virtualization is usually implemented via software applications.
Desktop Virtualization
A type of server virtualization technology which works at the OS layer. The physical server and single instance of the operating system is virtualized into multiple isolated partitions, where each partition replicates a real server. The OS kernel will run a single operating system and provide that operating system functionality to each of the partitions. Not to be confused with operating system virtualization.network virtualization: using network resources through a logical segmentation of a single physical network.
Application Virtualization
Application virtualization is the practice of running software from a remote server rather than on the user's computer. Dynamic link library (DLL) programs redirect all the virtualized application's calls to the server's file system. When software is run from the server in this manner, no changes are made to the local computer's operating system (OS), file system or registry. Computing resources are allocated based on changing requirements in real time.
