I already have a mysqld running on port 3306 on my linux system and want a second instance on a different port. This is a totally different instance, I don't want it to share data tables or anything else with the first instance. I tried running mysqld --defaults-file=config.conf where config.conf is my other config file with the new port and datadir, tried using absolute paths, everything, and kept getting this error: Could not open required defaults file: /PATH_TO_FILE/config.conf Fatal error in defaults handling. Program aborted Can anyone please help me? Everything about --defaults-file I find is about windows, how do I specify a custom config file on linux? Or is it possible to use the --datadir command line option (is there a command line option to specify the port also?) and would that create a totally unrelalted instance of mysqld?