Paravirtualization definition
Paravirtualization refers to a virtualization technique in which the guest operating system (the OS being virtualized) is aware of the fact that it's running in a virtualized environment and directly interacts with the underlying virtualization platform, or hypervisor. Because the guest OS is aware of the virtualization, it can make direct calls to the hypervisor for many operations instead of going through hardware emulation, which may result in better performance.
See also: hardware virtualization
Examples of paravirtualization
- Xen. While Xen also supports full virtualization, it initially gained attention for its paravirtualization approach. With paravirtualization, Xen requires guest operating systems to be modified to run efficiently on its hypervisor.
- VMware paravirtual SCSI controller. It provides an optimized interface between the VM and the hypervisor, delivering improved I/O performance compared to fully virtualized SCSI controllers.
- Paravirtualized network drivers. In some virtualization platforms, paravirtualized network drivers are used to enhance network I/O performance.
- VirtIO. VirtIO is a paravirtualized platform that provides a standard interface for I/O virtualization and is predominantly used with the kernel-based virtual machine hypervisor.
Paravirtualization use cases
- Data centers. Many data centers use paravirtualization for the performance benefits, especially if the overhead of full virtualization might be a concern.
- Cloud environments. Cloud service providers may employ paravirtualization to efficiently run multiple customer VMs on shared physical hosts.
- Development and testing: Paravirtualized environments may help simulate different systems and configurations without the need for a large amount of physical hardware.
