A detailed and fascinating multi-phase account of how to make a web site scale up: The Adventures of Scaling. The site in question is written in Ruby on Rails, though very little is specific to that framework. There's much more about the other web infrastructure surrounding Rails: proxy frontends, server topology, database replication, caching strategies, and so on. If you're building a dynamically generated web site that you'd like to make serve tons of pages per day, this is well worth a read.