yepp's post in rAthena on CentOS platform. was marked as the answer
MariaDB is a fork of MySql so it is 99% compatible and it is much better. Everything else is the same.
mysql -u(username) -p(password) (databasename) or
mysql -p
Like that. No difference. I also have CentOS in my server and I love its stability.
--EDIT--
Oh to answer your question, I see that you are using CentOS 7.
Try this:
sudo systemctl start mariadb
To check if it's installed:
rpm -qa | grep mariadb
In case mariadb-server is not installed:
sudo yum install mariadb-server
