I have two different VPSs with Vultr. Both are running latest Centminmod with PHP 7.0.11. This problem has happened for a while. When I update WordPress or a plugin, every site on my server becomes inaccessible and I receive error 500. The only thing that fixes this is restarting PHP-FPM. My permissions and ownership are set properly. Resetting them doesn't make the error 500 go away. I check the site error logs and the FPM error logs, but there's nothing related to the crash. My CPU, RAM, and storage aren't maxed out. Simply restarting FPM fixes things. But I'm concerned about the reliability of that, because if stuff is crashing, it's possible that upgrade processes aren't completing. Any ideas?