Believe it or not, server virtualisation has been around since 2001 when VMware first released a server virtualisation product. Since that time server virtualisation has grown enormously and is now the de facto method when deploying servers in an IT environment.

Virtualisation allows many virtual servers to reside independently on the same physical hardware. The software that provides this separation between the physical server and the virtual servers is called a hypervisor. There are currently two main server virtualisation products:

• Reduced cost – Instead of purchasing multiple physical servers, one server can host many virtual servers
• Server consolidation – Multiple servers can be replaced with a single server when they reach end of life, saving money and space in the server rack
• Shared resources – Critical resources such as memory and CPU can be shared across multiple virtual servers providing better utilisation of hardware
• Reduced management – Virtual servers have less management overhead primarily because they don’t talk directly to the hardware so there are fewer device driver