Pro Ubuntu Server Administration
Ubuntu Server Edition is a wonderful Linux distribution -- one of the last ones left to fit on a single CDROM. Out of the box, it provides no GUI and only the bare minimum services to boot up. So when you install it and see that blinking cursor, just what exactly can you do with Ubuntu Server? Pro Ubuntu Server Administration does a great job answering that question.
This book covers almost everything a System Administrator would want to do with Ubuntu Server: RAID, LVM, system management, clustering, file sharing, mail hosting, and security. It's crammed with commands and utilities you can follow along with to create a killer server. I especially enjoyed the clustering coverage. Not too many System Adminsitration books cover clustering at all. And while this book didn't nearly cover all aspects of clustering, it still gave you enough information to get a file share cluster up and running.
Oddly, this book did leave out services such as DNS and Web hosting, but the wealth of coverage in the other areas more than makes up for that. This is a highly recommended book to read for anyone working with, or is curious about, Ubuntu Server. You won't be disappointed.