Professional Xen Virtualization [Paperback]

I was the first person to post a review for this book, and it appeared on amazon but then it disappeared a week or so later and a 5 star review showed up... makes me wonder... At any rate this "re-review" will not be as complete as my first review.

This book is pretty low quality. The author is overly verbose for many things that are not really directly relevant. Case in point, the first 3 chapters are spent talking about virtualization in general, and then the alternative options to Xen. That would be fine if this book was titled "professional virtualization," but it is not... it is supposed to be about Xen, so why would the author waste a full 1/3 of the book telling us what else we might want to use?

The actual meat of the book, the stuff thats actually useful, is pretty much the exact same information you can get from the Xen handbook/users guide online. The author does not provide much if any further value or insight.

Finally the Author must have been hurting for a page count because the 10-15% (i had it actually calculated in my first review.. i believe it was 11%) is an appendix and command reference for Xen.

All in all, this book is not any thing worth spending money on if you are looking for a serious Xen guide. I would recommend one of the two following books over this one.

"Running Xen: A Hands-On Guide to the Art of Virtualization" (available 4/08)

or

"The Definitive Guide to the Xen Hypervisor" (currently available)

I really enjoyed reading Professional Xen Virtualization (PZV). The book answered exactly the right questions for me, a person who had no Xen experience but wanted to give the product a try. If you are looking for a book on Xen internals, you should read The Definitive Guide to the Xen Hypervisor by David Chisnall. If you are less concerned about source-code-level details but still want to learn a lot about Xen, you will definitely enjoy PZV.

William von Hagen is an excellent writer. I found it easy to follow his thought process and he delivers technical material very well. I found his coverage of Xen to be thorough and actionable. To try Xen I followed von Hagen's suggestion to boot Xenoppix, a live CD version. I used knoppix_v5.1.1CD_20070104_xen3.1.1_vbox-20071101.iso but as of this writing knoppix_v5.1.1CD_20070104_xen3.2.0_vbox-20080213.iso is available from the unit.aist.go.jp/itri/knoppix/iso/ FTP server. I am confident I could have installed Xen on dedicated hardware following the author's directions.

Several aspects of the book made it very useful to me. First, I liked the comparison to other virtualization products that appeared in part of Ch 2. That section gave me a better idea which product would be appropriate for my needs, especially when considering hardware support for virtualization and the differences between paravirtualized VMs and hardware virtualized VMs. Second, von Hagen often explains how and why a feature operates, rather than just listing what a feature offers. I appreciated this level of insight. Third, I liked seeing instructions for a variety of Linux distributions and the background on various Linux capabilities that could influence Xen deployment. These included logical volumes in Ch 6, initial RAM disks (initrd) vs initial RAM filesystems (initramfs) in Ch 4, and more.

I subtracted one star from the review for three factors. First, I would have liked some coverage on using NetBSD for Xen dom0 and domU. NetBSD has supported Xen in some fashion for many years and seems a priority for the OS. Second, one of the selling points for certain Linux distributions is their inclusion of tools for managing Xen VMs. While these are part of commercial distros (Red Hat, SUSE), the author could have described them more fully, or perhaps looked at Fedora's offering. Third, I could see how some of the background material on relevant but not Xen-specific Linux features might not be welcome in a book on Xen. For example, if I really want to know how to back up a system, I probably don't need to read about it here.

Overall, I was very pleased with PZV. I found earlier books on Xen to not provide enough detail to warrant reading and reviewing them. PZV, on the other hand, has all the material required to install and use Xen in production. I highly recommend it if you want to give Xen a try in your environment.

If you are looking to get familiar with Xen, (or Oracles xVM) this book is a pretty good starting point. It covers some of the lower level aspects of Xen most people may not even be aware of. Little things like how to properly construct an xml configuration file for your virtual machines, instead of typing out long command lines over and over.

Give it a read it's worthwhile, and still sits on my book shelf for some periodic referencing.