The use of system virtualization offers many benefits to organizations and the environment.  Among these are:

More efficient use of resources

In order to guarantee that sufficient resources are available to every user and application to satisfy business demands, organizations have typically overprovisioned systems, increasing capital and operating expenditures. With virtualization, capacity can be used more effectively, reducing the costs to acquire systems, the environmental (power cooling and real estate) costs required to run them, and the costs associated with managing the additional systems.

Fault isolation

An application error, operating system crash, or user error in one virtual machine will not affect the use of other virtual machines on the same system.

Increased security

By separating users and applications into different virtual machines, diverse user communities can use the resources of a single physical system securely, with their information and network traffic safely isolated from others.

Rapid provisioning

Because a virtual machine's disk storage is usually represented as files or logical volumes, standard storage management techniques such as file copy or volume cloning can be used to create new virtual machines rapidly, rather than requiring real "bare metal" installation of operating systems and applications, as non-virtual use of separate physical servers would require.  This cuts the time to set up a new system (including hardware acquisition and racking, software installation and configuration) from weeks to minutes.

Portability

The use of abstract devices within virtual machines, combined with the encapsulation of virtual data in file-backed or volume-backed virtual disks, makes it easy to move virtual machines from one physical system to another, for maintenance, more effective resource utilization, or simply for replicated provisioning. In many cases, running virtual machines can even be moved while they are online, with no interruption to service.