MySQL max_connections 设置没用总是 200多解决

It was indeed limits set by the OS. Resolved it with :

Edit file /usr/lib/systemd/system/mysqld.service
Add at end:

LimitNOFILE=65535
LimitNPROC=65535

$ systemctl daemon-reload

启动mysql
$ systemctl restart mysqld.service 或 service mysql start