I installed mysql using yum install mysql-server on centos 5.9 and realized it's version 5.0. I need version 5.5 so then I did yum install mysql55-server however I couldn't find a way to start server version 5.5 instead of 5.0. service mysqld start will start 5.0 server and removing mysql 5.0 doesn't help either because service mysqld start fail to find mysqld service Update 1 Nov 2013: I noticed mysql55 package was being installed to /opt/rh/mysql55/root/usr/bin, so I appended that into the start of my PATH env var but service mysqld start still runs 5.0 server. If I tried running the server using mysqld_safe located on above mysql55 path but it says [root@***** bin]# mysqld_safe Use "scl enable mysql55 'service ...'" invocation Not quite sure what it means. I checked the running mysql version by connecting to it using mysql command line client. [root@***** bin]# mysql Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 2 Server version: 5.0.95 Source distribution