Xen and the Art of Virtualisation
Numerous systems have been designed which use virtualisation to
subdivide the ample resources of a modern computer. Some require
specialized hardware, or cannot support commodity operating systems.
Some target 100% binary compatibility at the expense of
performance. Others sacrifice security or functionality for speed.
Few offer resource isolation or performance guarantees; most provide
only best-effort provisioning, risking denial of service.
In this talk I present Xen, an x86 virtual machine monitor which
allows multiple commodity operating systems to share conventional
hardware in a safe and resource managed fashion, but without
sacrificing either performance or functionality. This is achieved by
providing an idealised virtual machine abstraction to which operating
systems such as Linux, BSD and Windows XP, can be ported with minimal
Our design is targeted at hosting up to 100 virtual machine instances
simultaneously on a modern server. The virtualisation approach taken
by Xen is extremely efficient: we allow operating systems such as
Linux and Windows XP to be hosted simultaneously for a negligible
performance overhead --- at most a few percent compared with the
unvirtualised case. We considerably outperform competing commercial
and freely available solutions in a range of microbenchmarks and