The purpose of virtualisation is that it allows one server to the job of multiple computers, by sharing the resources of a single computer across multiple environments. Thus, allowing service providers to use hardware more efficiently by running many virtual servers on each machine in a data centre.
Installing traditional physical servers would typically require a separate server for each server role. By utilising virtual server technology the number of physical servers can be greatly reduced as virtual servers are consolidated on to fewer incidences of physical hardware.
Virtualising servers will result in improved resource utilisation as well as reductions in real estate, power and cooling requirements. In addition to energy saving and lower capital expenses due to more efficient use of hardware resources, virtualisation provides high availability of resources, increased security, and improved disaster recovery processes.