Setup Drupal 7 Panopoly distribution with mongoDB on CentOS 7
The mongoDB provides high performance, high availability, and easy scalability. Using it with Drupal, will take some load off its SQL database. The read/write SQL procedures in Drupal functions like: session, log entries from watchdog, cache, fields, queue and block can be handled by mongoDB Drupal module. And this will greatly improve the perfomance of your Drupal site.