This issue has been driving me crazy for months. No matter whether I have 20 visitors or 200 concurrent visitors, the issue happens when an author, in WordPress, saves or updates a post. What happens is that it spawns dozens of lsphp processes that cause the server load to skyrocket and then it's 503s for everyone. Not good. Then, it might clear up over 2, 5, 10 minutes…you never know. My emergency response is to pkill the lsphp processes to flush them out.
I used Litespeed plugin to disable Heartbeat and it didn't change anything. To be clear, the call is coming from inside the house and only occurs when someone is inside WP saving or updating a post. There is no evidence these slowdowns are caused by traffic surges. No related Cloudflare WAF rules are being tripped. Nothing egregious is happening in the browser developer tools The site itself is blazing fast…so long as someone isn't editing in WP. FWIW I'm using A2 for hosting on a VPS. Any help is MUCH appreciated!