If the php process is taking up way too much RAM, it’s possible that your code has a memory leak of some sorts. I would suggest using https://github.com/barryvdh/laravel-debugbar to profile your application’s memory usage and see what’s taking up so much RAM.

Examine dmesg and log files for signs of mysql crashing. Very likely it’s killed for out of memory errors.

Post memory profile like the output of free(1).

Ensure you have swap enabled.

In my experience at least 2Gb RAM is required for running PHP-FPM in production along with mysql/redis.

As another option you could run mysql on a second droplet and enable local networking for both of them. That way when your php application hogs too much memory the OOM killer will only murder your webserver workers and not your mysql database. (You’ll have to connect to your database via tcp instead of unix sockets though).

As a plus you can also increase the size of each droplet as each sides needs grow, rather than hoping they don’t step on each others’ toes, there’s also less risk of mysql losing data when it’s randomly killed.