In some cases, after an unplanned reboot of the server, when starting the MySQL service, the error “Another MySQL daemon already running with the same unix socket».
To fix the situation, you need to delete the socket file by running the command:
rm -rf /var/lib/mysql/mysql.sock
After that you need to restart MySQL:
service mysqld restart
For Debian and Ubuntu, the same command looks a little different:
service mysql restart