Performance

Drupal with millions of nodes - Tuning MySQL for Drupal - Performance Tuning Apache and MySQL for Drupal - The following articles discuss performance tuning and optimization of Drupal - Drupal performance tuning  

Memcache: Distributed Caching with Memcached - Memcache API and Integration - Your Drupal On Memcached

Pressflow is a a derivative of Drupal core providing enhanced performance, scalability, and data integrity.  Project Mercury: is a pre-configured Drupal+Varnish EC2 AMI

aBits articles