The Art of Scalability: Scalable Web Architecture, Processes, and Organizations for the Modern Enterprise (2nd Edition) by Martin L. Abbott and Michael T. Fisher
Cloud Computing for Complete Beginners: Building and Scaling High-Performance Web Servers on the Amazon Cloud by Ikram Hawramani
Even Faster Web Sites: Performance Best Practices for Web Developers by Steve Souders
Getting Started with Memcached by Ahmed Soliman
High Performance Drupal: Fast and Scalable Designs by Jeff Sheltren, Narayan Newton and Nathaniel Catchpole
Instant Varnish Cache How-to by Roberto Moutinho
MySQL High Availability: Tools for Building Robust Data Centers by Charles Bell, Mats Kindahl and Lars Thalmann