In IT, virtualisation is the process of creating logical computing resources from available physical resources. This is accomplished using virtualisation software to create a layer of abstraction between workloads and the underlying physical hardware. Once installed, the virtualised computing resources such as memory, CPUs, network and disk I/O and storage can all be pooled and provisioned to workloads without regard for physical location within a data centre.
Virtualisation technology provides encapsulation that prevents workloads from accessing resources that are not assigned to it which allows a virtualised system to support multiple independent workloads simultaneously. Virtualisation is used to consolidate IT infrastructure, centralise system administration and management tasks, support workload scalability and agility and optimise the use of computing resources. This concept is the foundation of server consolidation, which has been the principal driver for virtualisation adoption.
Virtualisation technology includes:
- Server virtualisation - abstracts the server’s physical computing resources into logical entities that are provisioned to multiple workloads, allowing far more workload to exist independently on the same physical host and increasing the server’s utilisation.
- Storage virtualisation - abstracts and pools the storage resources available within the data centre, and allows storage to be provisioned to workloads that require it. This reduces the incidence of lost or “orphaned” storage and increases storage utilisation. Mainly on a storage area network (SAN).
- Network virtualisation - allows a large physical network to be provisioned into multiple smaller logical networks, and conversely allows multiple physical LANs to be combined into a larger logical network. This behaviour allows administrators to improve network traffic control, organisation and security.
- Desktop virtualisation - runs a complete desktop instance on a centralised server rather than the individual desktop PC, and provides that instance to a remote endpoint such as a simple thin client. Centralising desktop instances in the data centre allows better manageability and security.
- Application virtualisation - used to virtualise specific applications rather than entire desktop instances. The virtualised application is operated on a centralised server and streamed across the LAN or WAN to client users that need access to that application. Application and desktop virtualisation are often used in tandem.
- Mobile virtualisation - allows multiple instances to exist on a smartphone, tablet or other mobile device.
Despite its benefits, the virtualisation penetration rate in the UK is only 29% in the third quarter of 2011, according to virtualisation industry survey, V-Index. Other European countries including Germany and France are ahead of the UK at 44.1% and 38.9% adoption rates respectively for the same period.