Overview of cache, data backup, and log concepts. Task on clearing the cache is covered. Part of the Drupal User Guide.
Overview of the cache and the site data that can be cached.
How to clear the cache using Drush or the user interface.
Overview of data backups and what should be backed up on a site.
Overview of logs and where to find recent log messages.
Overview of the status report and where to find it on a site.