I think it'd be interesting to highlight some vaguely security-related measures that might make it less simple for attackers to shut down your site just by usin

I think it'd be interesting to highlight some vaguely security-related measures that might make it less simple for attackers to shut down your site just by using it normally. I'm not so sure it's relevant to the SO question, mind, as it's more in line with optimisation than anything. This might include: * Using a caching layer to store and re-use the results of complex, infrequently changing queries, instead of querying the database on every request. * Using a message queue to handle the processing of certain things in the background. If you have an upload form that then manipulates or processes the file in some non-trivial manner, add it to the queue. The queue can drop messages or jobs if it gets too big. I only say this having developed some projects where holding the refresh key down for a few seconds on pages with lots of queries (along with the hundreds Drupal makes anyway) could crash MySQL. As could using a separate form that sent emails and processed images on-the-fly. Best not to present attackers prime opportunities to DOS your site.