[[email protected]:/var/log]# systemctl start mysqld

[6]+  已停止               systemctl start mysqld

-----------------長時間等待，不能結束，強行終端------------------

檢視狀態

[[email protected]:/var/log]# systemctl status mysqld

● mysqld.service - MySQL Community Server

   Loaded: loaded (/usr/lib/systemd/system/mysqld.service; enabled; vendor preset: disabled)

   Active: activating (start-post) (Result: exit-code) since 五 2016-01-08 14:24:37 CST; 4min 50s ago

  Process: 5012 ExecStart=/usr/bin/mysqld_safe (code=exited, status=1/FAILURE)

  Process: 5001 ExecStartPre=/usr/bin/mysql-systemd-start pre (code=exited, status=0/SUCCESS)

 Main PID: 5012 (code=exited, status=1/FAILURE);         : 5013 (mysql-systemd-s)

   CGroup: /system.slice/mysqld.service

           └─control

             ├─5013 /bin/bash /usr/bin/mysql-systemd-start post

             └─6366 sleep 1

1月 08 14:24:37 cnski mysqld_safe[5012]: 160108 14:24:37 mysqld_safe Logging to '/var/log/mariadb/mariadb.log'.

1月 08 14:24:37 cnski mysqld_safe[5012]: touch: cannot touch ‘/var/log/mariadb/mariadb.log’: Permission denied

1月 08 14:24:37 cnski mysqld_safe[5012]: chmod: cannot access ‘/var/log/mariadb/mariadb.log’: Permission denied

1月 08 14:24:37 cnski mysqld_safe[5012]: 160108 14:24:37 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql

1月 08 14:24:37 cnski mysqld_safe[5012]: /usr/bin/mysqld_safe: line 129: /var/log/mariadb/mariadb.log: Permission denied

1月 08 14:24:37 cnski mysqld_safe[5012]: /usr/bin/mysqld_safe: line 166: /var/log/mariadb/mariadb.log: Permission denied

1月 08 14:24:37 cnski mysqld_safe[5012]: touch: cannot touch ‘/var/log/mariadb/mariadb.log’: Permission denied

1月 08 14:24:37 cnski mysqld_safe[5012]: chown: cannot access ‘/var/log/mariadb/mariadb.log’: Permission denied

1月 08 14:24:37 cnski mysqld_safe[5012]: chmod: cannot access ‘/var/log/mariadb/mariadb.log’: Permission denied

1月 08 14:24:37 cnski systemd[1]: mysqld.service: main process exited, code=exited, status=1/FAILURE

原因：替換Mariadb是未能刪除替換my.cnf，

解決：

修改my.cnf

log-error=/var/log/mariadb/mariadb.log
pid-file=/var/run/mariadb/mariadb.pid

至

[mysqld]
datadir=/var/lib/mysql
socket=/var/lib/mysql/mysql.sock
user=mysql
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0

[mysqld_safe]
log-error=/var/log/mysqld.log
pid-file=/var/run/mysqld/mysqld.pid