How to increase open files limits for MariaDB

Introduction

The my.cnf open_files_limit setting may not be taken as a variable and needs to be set via systemd on CentOS 7.

Procedure

Create the file

/etc/systemd/system/mariadb.service.d/limits.conf

and paste the following into that file

[Service]
LimitNOFILE=40000

Then run the following to load that change and restart MairaDB.

systemctl daemon-reload
/scripts/restartsrv_mysql