Bei Gelegenheit unbedingt lesen und nachbauen: A moment of Xen: Virtualize Linux to test your apps:
“Xen is a paravirtualization technology available for the Linux kernel that lets you enclose and test new upgrades as if running them in the existing environment but without the worries of disturbing the original system. This article shows you how to install a Xen system that will give administrators a valuable sandbox for testing system upgrades (as well as a playground for running multiple virtual machines on the same Linux box). Take a look at virtualization on Linux and see the benefits that come from using Xen in that space.”