"Linux-VServer offers a simple way to run several virtual
servers on one piece of physical hardware. While it lacks some of
the flexibility of more complex virtualization schemes, it is
simple to implement and is capable of excellent performance.
"Linux-VServer, and similar software like OpenVZ, take a
'lightweight' approach to virtualization, essentially segmenting a
single Linux kernel environment into virtual machines with separate
file systems, process tables, and network addresses..."