Drupal Finding and killing anonymous sessions in Drupal Sessions in Drupal are created when you log into Drupal. You can however start a session without first authenticating. This is known as an anonymous session
Caching CORS, Cache poisoning and the Vary HTTP header Understanding the Vary header is key ensuring CORS will work with CDNs and caching.
Performance Preparing for a high traffic event, simple steps to success The steps that any new launch or high traffic event should go through in order to have the best chance of success.
Drupal Dynamic content caching based on attributes in Drupal 7 Simple code to maximise your varnish hitrate
Drupal Debugging Drupal performance with Cache Debug module Finding the offenders breaking your caching strategy