MySQLTuner is a script that will assess MySQL performance and recommend steps to maximize performance. To install and run MySQLTuner, log in to your VPS as the root user and follow these steps (for CentOS):
1. Download MySQLTuner:
# wget http://mysqltuner.com/mysqltuner.pl
# chmod 755 mysqltuner.pl
2. Run MySQLTuner:
Configuration can be set in the /etc/my.cnf file.