This script signals the health of a Drupal website by checking the following criteria:
- main database responds to queries
- slave database (if configured) responds to queries
- Memcached instances are available
- files directory is writeable
- temp directory is writeable
If at least one of these checks fails, the script returns a server error (code 500).
Simply put the script into the root directory of your Drupal installation. Configure your load balancer to call it in its health check.
This script is based on the status.php script from the Lullabot blog post "Configuring Varnish for High-Availability with Multiple Web Servers".
It has been adapted for DrupalCONCEPT High Performance Drupal Hosting by Jochen Lillich jochen@freistil.it.