Virtualization is the latest in a long line of technical innovations designed to increase the level of system abstraction and enable IT users to harness ever-increasing levels of computer performance.

At its simplest level, virtualization allows you to have two or more computers, running two or more completely different environments, on one piece of hardware. For example, with virtualization, you can have both a Linux operating system and a Microsoft Windows operating system on one server. Alternatively, you could host a Windows XP desktop and a Windows 7 desktop on one workstation.

In slightly more technical terms, virtualization essentially decouples users and applications from the specific hardware characteristics of the systems they use to perform computational tasks. This technology is likely to usher in an entirely new wave of hardware and software innovation. For example, and among other benefits, virtualization can simplify system upgrades (and in some cases may eliminate the need for such upgrades) by allowing users to capture the state of a virtual machine (VM), and then transporting that state in its entirety from an old to a new host system.

Virtualization is also designed to enable a generation of more energy-efficient computing. Processor, memory, and storage resources that today must be delivered in fixed amounts determined by real hardware system configurations will be delivered with finer granularity via dynamically tuned VMs.

Virtualisation can be classified into 3 categories, namely:-

Why Virtualisation?

The key benefit to virtualising the desktop is total cost of ownership. Companies can diminish overall TCO by dramatically reducing desktop management, extending lifecycles of hardware and lowering power and cooling costs. Some other benefits include:

  • Reduce maintenance costs
  • Increase security
  • Easy deployment- ability to setup up workgroups in very little time
  • Reduce energy costs
  • Centralized management
  • Less downtime/greater productivity

Desktop Virtualisation

Desktop virtualization, often called client virtualization, is a virtualization technology used to separate a computer desktop environment from the physical computer. Desktop virtualization is considered a type of client-server computing model because the "virtualized" desktop is stored on a centralized, or remote, server and not the physical machine being virtualized.

Desktop virtualization "virtualizes desktop computers" and these virtual desktop environments are "served" to users on the network. You interact with a virtual desktop in the same way you would use a physical desktop. Another benefit of desktop virtualization is that is lets you remotely log in to access your desktop from any location.

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Server Virtualisation

Server virtualization is 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.

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Storage Virtualisation

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 sub-network of shared storage devices. The management of storage devices can be tedious and time-consuming. Storage virtualization helps the storage administrator perform the tasks of backup, archiving, and recovery more easily, and in less time, by disguising the actual complexity of the SAN.
Users can implement virtualization with software applications or by using hardware and software hybrid appliances. The technology can be placed on different levels of a storage area network.

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