Virtualization is a term used to describe a variety of computing technologies. Virtualization technology enhances and extends an organization's computing resources by creating a separation between the hardware and the software that runs on it. This separation can be leveraged to create simulated or virtual computing resources.
Virtualization technology comes in several different varieties. In the early days of virtualization, the term typically meant server virtualization. With server virtualization technology, a physical server called the host is separated into several virtual guest servers. These virtual servers can run different operating systems and software, making them ideal when testing new applications on various operating systems. The server consolidation that occurs through virtualization reduces the hardware resources required and the associated expense.
Desktop virtualization technology also helps companies reduce hardware costs. By using desktop virtualization, a user gets his full desktop experience from a low-end computing device. The server can host many virtual desktops, each running different operating systems and applications. Desktop virtualization cuts down on hardware and energy costs, and allows system administrators to easily provision new desktops and roll out new software.
Storage virtualization technology separates virtual storage partitions from physical storage devices. The virtualization software presents users with a logical storage area for storing their data, and maps that data to its actual physical location. Virtualizing storage gives administrators greater control over storage resources and allocation of storage space for applications and users that need it most. Data migration is also made easier through storage virtualization. Data can be moved to another storage device without disrupting computer operations. It's also easier to expand storage space when the physical location is full.
Other types of virtualization include data virtualization, application virtualization, and network virtualization. Data virtualization transparently lets users access data from several different physical locations. Application virtualization separates applications from the operating system. It allows the application to run on a remote computer instead of on the user's computer. With network virtualization, a network can be partitioned into several virtual networks that each have a different purpose and can run concurrently.
Virtualization technology has allowed organizations to improve operational efficiency while reducing hardware and space requirements, energy consumption, and maintenance headaches. It also provides a layer of security because the virtualization applications run independently of each other so that a problem with one server can be confined to that server, and will not spread to others.