centos7mysql:mariadbwaitready$MAINPID(code=exited,status=1/FAILURE)

在centos7环境上重装mysql时运行命令
删除:#yum remove mariadb* 
重装:#yum -y install mariadb*
启动：#systemctl start mariadb.service 此时数据库启动报错
查看启动状态:#systemctl status mariadb -l
mariadb.service - MariaDB database server
   Loaded: loaded (/usr/lib/systemd/system/mariadb.service; enabled)
   Active: failed (Result: exit-code) since Wed 2015-01-07 22:47:01 EST; 9s ago
  Process: 19037 ExecStartPost=/usr/libexec/mariadb-wait-ready $MAINPID (code=exited, status=1/FAILURE)
  Process: 19036 ExecStart=/usr/bin/mysqld_safe --basedir=/usr (code=exited, status=0/SUCCESS)
  Process: 19009 ExecStartPre=/usr/libexec/mariadb-prepare-db-dir %n (code=exited, status=0/SUCCESS)
 Main PID: 19036 (code=exited, status=0/SUCCESS)

Jan 07 22:47:00 JX-Store systemd[1]: Starting MariaDB database server...
Jan 07 22:47:00 JX-Store mysqld_safe[19036]: 150107 22:47:00 mysqld_safe Logging to &＃39;/var/log/mariadb/mariadb.log&＃39;.
Jan 07 22:47:00 JX-Store mysqld_safe[19036]: 150107 22:47:00 mysqld_safe Starting mysqld daemon with databases from /var/lib/mysql
Jan 07 22:47:00 JX-Store mysqld_safe[19036]: 150107 22:47:00 mysqld_safe mysqld from pid file /var/run/mariadb/mariadb.pid ended
Jan 07 22:47:01 JX-Store systemd[1]: mariadb.service: control process exited, code=exited status=1
Jan 07 22:47:01 JX-Store systemd[1]: Failed to start MariaDB database server.
Jan 07 22:47:01 JX-Store systemd[1]: Unit mariadb.service entered failed state
网上查了下，有的说是权限问题，设置了/var/lib/mysql 这个目录的权限扔不起作用
配置/etc/my.cnf 文件也不起作用
解决办法:
最后，我删除了/var/lib/mysql  和 /etc/my.cnf 重新安装就没有错了。
/var/lib/mysql 这个目录重装完后是不存在任何数据的，但是启动后产生了许多文件 如:mysql.sock,如果想直到为何会这样只能查看mysql官网了