The vSphere virtualization layer decouples the application from the underlying physical resources. This decoupling enables greater flexibility in the application layer by eliminating hardware downtime for maintenance and changes to the physical system without affecting the hosted applications. In a server virtualization use case, this layer enables multiple independent virtual machines (VM) to share the same physical hardware.
vSphere is a complete and robust virtualization platform, virtualizing business-critical applications with dynamic resource pools for flexibility and reliability. It transforms physical resources of a computer by virtualizing the CPU, RAM, hard disk, and network controller. This transformation creates fully functional VMs that run isolated and encapsulated operating systems and applications.