A virtual dedicated server (VDS, also referred to as Virtual Private Server or VPS) is a method of partitioning a physical server computer into multiple “virtual” servers such that each has the appearance and capabilities of running on its own dedicated machine. Each virtual server can run its own full-fledged operating system, and each server can be independently controlled/rebooted/resized/migrated.
There are two kinds of virtualisation: software based and hardware based. In a software based virtual environment, the virtual machines share the same kernel and actually require the main node’s resources. This kind of virtualization normally has many benefits in a web hosting environment because of quota incrementing and decrementing in real time with no need to restart the node. The main examples are Xen, Virtuozzo, Vserver, and OpenVZ (which is the open source and development version of Parallels Virtuozzo Containers).
