MySQL manager or server PID file cocould not be found solved # My server hostname, mysql pid file default name is hostname. pid, if not in/etc/my. in cnf, If you specify a specific pid filename and pid file path, this file is associated with mysql Data. [Root @ redhat var] # hostnameredhat switch to mysql data dir through # (in the mysql data file directory) # Your mysql data dir may be different from mine, my options are/var/lib/mysql/var/[root @ redhat var] # cd/var/lib/mysql/var/get the pid of the mysql process that the mysql user runs, then import it to hostname. in the pid file, [root @ redhat var] # echo 'ps aux | grep mysql | grep "user = mysql" | grep-v "grep" | awk '{print $2 }' '> redhat. pid # note the redhat here. pid is related to hostname. Here is my hostname. pid changes the file owner and owner group to mysql: mysql [root @ redhat var] # chown mysql: mysql redhat. pid