Virtualization
Virtualisation helps you consolidating servers. Like partitioning a harddisk, it is possible to partition a server as well. With a specialized software it is possible to run different Operating System on the same piece of hardware at the same time. For the Operating Systems it seems as if they are running on a dedicated machines. You can utilize one fast server for running different heterogeneous Operating Systems with different tasks. This frees space within the data center and lowers energy consumption without loosing the advantages of a dedicated server.
Xen Hypervisor
Xen is an Open Source Hypervisor for paravirtualization and hardware based virtualization on Intel based hardware. It's performance is outstanding, while feature-rich, if you compare it to other solutions. It is licensed under the GPL. Thus it is free of charge. However if you need support or other services you might want to opt for the Enterprise Edition. This commercial Edition provides added value for corporate clientsXen Basics
This document is intended to give you a first insight on Xen, how it operates, how to install and administrate it. It will help you getting started with your first Xen installation. Furthermore it will help you to avoid some common pitfalls.
Xen Hints
Here I'm gathering pieces of information rather than tutorials. But I'm convinced that they might also be useful to others. Besides some problems I encountered, you can expect to find some help on troubleshooting problems on Xen.