Professional Xen® Virtualization

Chapter 5. Configuring and Booting Virtual Machines

The previous chapter discussed how to get a domain0 system up and running, highlighting some common problems, concerns, and solutions. However, having a domain0 system up and running without any guest domains is pretty equivalent to simply having a Linux system running in the first place. Aside from the fact that the Xen hypervisor gives you even more knobs to twist than a standard Linux system, it's not really all that exciting until you bring up your first virtual machine.

As explained in the first two chapters of this book, Xen supports both paravirtualized systems and hardware virtualization, the latter only if it is supported by your hardware. Once you have a valid HVM domainU configuration file, hardware virtual machines are pretty easy to install and use as a standard domainU system because you install and create them using standard OS installation disks. On the other hand, paravirtualized systems are more interesting for a few reasons, most notably because they typically provide higher performance than hardware virtual machines, and work on a much wider range of hardware than hardware virtual machines can. If all of your systems are brand-new, 64-bit Intel-VT or AMD SVM hardware, I'm proud to know you and somewhat jealous. On the other hand, if your machine room already has a significant investment in powerful 32-bit or non–HVM-compatible 64-bit machines, it's hardly cost-efficient to simply replace that hardware because ...