Server virtualisation is built upon the widely accepted practice of hardware virtualisation which has made it possible to run multiple operating systems and multiple applications on the same computer at the same time. It has transformed a significant portion of IT infrastructure and offers new ways for organisations to meet challenges of improving hardware utilisation and drive down costs.
The core idea of hardware virtualisation is simple: Use software to create a virtual machine (VM) that emulates a physical computer. This creates a separate OS environment that is logically isolated from the host server. By providing multiple VMs at once, this approach allows running several operating systems simultaneously on a single physical machine.
Rather than paying for many under-utilised server machines, each dedicated to a specific workload, server virtualisation allows consolidation of those workloads onto a smaller number of more fully-used machines. This implies fewer people to manage those computers, less space to house them, and fewer kilowatt hours of power to run them, all of which saves money.