Links and resources on Drupal performance tuning and optimization

This is a collection of performance tuning and optimization articles on the web.

If you happen to write a useful article on scalability of Drupal or xAMP, or you ran across such articles on the web, please contact us with the URL and we will add it below. 

• A set of articles at Nadeau Software on Essential performance tuning for Drupal web sites. The articles are informative and well written. However, they focus on sheer performance (with low concurrency) as opposed to scalability (high concurrency). For example, no mention of contention areas, bottlenecks and such when having very high traffic. There is more performance articles under this tag.
• An article titled Surviving the Digg effect by Ivan Raszl, founder of Ads of the World. It has details on how it went with graphs. 2bits setup Drupal, and tuned the server for maximum performance. The funniest part is that the other server where Creative Bits is hosted, and had the article on Digg was posted was not tuned, and hence lasted only 15 minutes because two articles from that site were on Digg's front page in addition to the article form Ads of the World.
• Mike Gifford of OpenConcept has a neat trick of how to do Drupal static page caching using Apache's rewrite.
• Tuning LAMP is a multipart series at IBM developerWorks.
  • Understanding the LAMP architecture.
  • Optimizing Apache and PHP.
• An article on Drupal Scalability at National Novel Writing Month. The article specifically points to two bottlenecks: Node Access joins in the database, and the use of LOWER() to match users.
• Kris Buytaert writes on NFS as a potential bottleneck.Comments on the page tend to lean towards NFS not being a real problem these days, although it used to be so historically.
• A series of detailed articles on scaling Drupal by John Quinn.