On my last blog post we looked to what Drupal achieves out of the box regarding Drupal caching. We understood how Drupal can cache pages for anonymous users and found solutions to avoid to bootstrap Drupal to serve a cached page (using a reverse proxy like Varnish or redirecting requests using Boost). We also saw that even if any of these tools is used, Drupal is also able to save cached versions of pages in the database. However, Drupal allows to plug transparently other caching backends that are faster:
