My friend Theo Schlossnagle has for many years run one of the most popular tutorials at ApacheCon, Scalable Internet Architectures. In this tutorial he covers the ways he has built successful, resilient and very large-scale server farms.
Theo doesn’t believe in the traditional big-iron, expensive-database scheme for making these things, preferring tools like Spread, Backhand and Wackamole. Anyway, to cut to the chase, he has, at long last, written a book about it – which I’ve just finished reading. If you’ve ever built a server farm, you’ll find the first few chapters easy going, but after that he dives into the technical details rapidly and lucidly. I recommend it highly.