I've been using RDS for years, and this only became an issue a few months ago. I was pulling my hair out trying to find the source of the issue... only to figure out it's suddenly RDS.
I've made no configuration changes or anything, but now I can see that when RDS does a backup of my MySQL 5.6.34 database, it is kicking off all the clients and doesn't accept connections and queries until it finishes.
https://forum.ghost.org/t/back-with-the-ghost-sites-failing-to-load-following-an-aws-rds-maintenance-backup-window/1983/3 I wound up finding a similar problem that someone is experiencing here, but with no solution to it figured out.
What changed and how do I resolve this?