I work on several high traffic Drupal sites that get millions of page views per month. These sites require special fine tuning to make sure they stay online under heavy load and serve pages to users quickly.
Tuning a Drupal site for performance involves looking at several layers of the web application.
- The Web Server
- The PHP code
- The Database and queries
- HTML Components
Items 1 to 3 are in the category of Back End Performance and involve delivering the main HTML document to the user's browser as quickly as possible. Items 4 and 5 are in the category of Front End Performance and involve speedily loading page components like images, styling, Flash objects and dynamic widgets.
Over the next couple of weeks, I'll be writing about each of these performance layers taking a look at solutions from Drupal's core perfomance features, performance-related contributed modules and tools that are not Drupal-specific.