"Using Xen you can separate your applications into
different virtual machines that are totally independent from each
other (e.g. a virtual machine for a mail server, a virtual machine
for a high-traffic web site, another virtual machine that serves
your customers' web sites, a virtual machine for DNS, etc.), but
still use the same hardware. This saves money, and what is even
more important, it's more secure. If the virtual machine of your
DNS server gets hacked, it has no effect on your other virtual
machines. Plus, you can move virtual machines from one Xen server
to the next one."
