How to handle if Drupal site goes down, show a static fallback page instead? One of my sites went down with the following mysql server down message: 



How can I show a basic static page when something fatal like this happens? Are there any modules that do this already? What are some other solutions if a site goes out. I tried cloudflare, but they don't already detect the site going down and still show a fatal message. It would be good if users were shown a static page instead.
Because Drupal is completely unresponsive when this happens, it's not something you can fix within Drupal.

Setting a static fail page is possible within your web server - most likely Nginx or Apache. If you are using a CDN, you can also configure it to display only cached versions of your pages if your server is unresponsive.

You'll have to consult your server documentation to get your answer.