Server Virtualization is the process of Partitioning a single server to appear as multiple servers. The physical server runs a hypervisor which is tasked with releasing, creating, and managing the resources of virtual machines or “guest” operating systems.
From physical server some amount of resource share is allocated to guest operating systems, typically in a manner in which the guest is not aware of any other physical resources save for those allocated to it by the hypervisor.
Virtual Private servers runs its own copy of operating system, superuser-level access will be given to the customers have for th operating system instance, and can install almost any software that runs on the OS; however, due to the number of virtualization clients typically running on a single machine, a VPS generally has limited processor time, RAM, and disk space
Why Server Virtualization: Due to the limitations of x86 servers, many IT organizations must deploy multiple servers, each operating at a fraction of their capacity, to keep pace with today’s high storage and processing demands. The result: huge inefficiencies and excessive operating costs.
Virtualization relies on software to simulate hardware functionality and create a virtual computer system. This enables IT organizations to run more than one virtual system – and multiple operating systems and applications – on a single server. The resulting benefits include economies of scale and greater efficiency.