A paravirtualized operating system does not require whole system emulation. The management module, or hypervisor, in a paravirtualized mode, operates within a paravirtualized operating system that has been modified to work in a virtual machine.

Generally, a paravirtualized operating system performs better than a fully virtualized operating system, in which all system elements must be emulated. However, this efficiency is offered at the cost of security and flexibility. Flexibility is compromised because the OS requires modification to run in paravirtualized mode. Security is compromised because the guest OS has more control over the underlying hardware, thereby increasing risk to the lower-level hardware, which can affect all guest operating systems running on the host.

Paravirtualization’s efficiencies also can result in better scaling. Paravirtualization requires only two percent processor use per guest instance per processor, versus full virtualization, in which processor use is 10 percent per guest instance per processor.

A paravirtualized operating system can reduce overall performance degradation by relocating critical task execution from the virtual domain to the host domain.