It is a method of logically dividing mainframes to simultaneously allow multiple applications to run concurrently. Bare metal applications were unable to cope up with the advancements to use abundance availability of resources such as the server processing power and capacity improvements. This paved way for designing virtual machines (VMs), by running specialized software on top of physical servers to emulate a type of underlying hardware system.

The same physical server can host multiple VM, each with different operating systems. Each VM runs a unique operating system and its own binaries/libraries and applications that it supports and services. VMs can be many gigabytes large. Server virtualization benefits are like a consolidation of applications onto a single system, with reduced server footprint, quicker server provisioning, improved disaster recovery, and cost savings.