今天下载了一个mysql5.7.18源码，装着玩，没想到安装了一上午都没有完成，不停报错，最后发现竟然是错误日志权限导致的。真是魔鬼藏在细节中啊。重要的事情说三遍：注意细节，注意细节，注意细节！！
[root@mysql5-7-18 ~]# chown root:root /usr/local/mysql/log/mysql_mysql-5-7-18.err
[root@mysql5-7-18 ~]# ll /usr/local/mysql/log/      
total 40
-rwxr-xr-x. 1 root  root  9357 May 31 14:13 mysql_mysql-5-7-18.err
-rwxr-xr-x. 1 mysql mysql  177 May 31 11:33 ray-bin.000001
-rwxr-xr-x  1 mysql mysql  177 May 31 14:05 ray-bin.000002
-rwxr-xr-x  1 mysql mysql  177 May 31 14:07 ray-bin.000003
-rwxr-xr-x  1 mysql mysql  177 May 31 14:09 ray-bin.000004
-rwxr-xr-x  1 mysql mysql  573 May 31 14:13 ray-bin.000005
-rwxr-xr-x  1 mysql mysql  180 May 31 14:09 ray-bin.index
-rwxr-xr-x. 1 mysql mysql  925 May 31 14:09 slow-log.log
[root@mysql5-7-18 docs]# service mysqld start
Starting MySQL.The server quit without updating PID file (/[FAILED]l/mysql/data/mysql5-7-18.pid).
[root@mysql5-7-18 ~]# chown mysql:mysql /usr/local/mysql/log/mysql_mysql-5-7-18.err    
[root@mysql5-7-18 ~]# ll /usr/local/mysql/log/                                     
total 40
-rwxr-xr-x. 1 mysql mysql 9357 May 31 14:13 mysql_mysql-5-7-18.err
-rwxr-xr-x. 1 mysql mysql  177 May 31 11:33 ray-bin.000001
-rwxr-xr-x  1 mysql mysql  177 May 31 14:05 ray-bin.000002
-rwxr-xr-x  1 mysql mysql  177 May 31 14:07 ray-bin.000003
-rwxr-xr-x  1 mysql mysql  177 May 31 14:09 ray-bin.000004
-rwxr-xr-x  1 mysql mysql  573 May 31 14:13 ray-bin.000005
-rwxr-xr-x  1 mysql mysql  180 May 31 14:09 ray-bin.index
-rwxr-xr-x. 1 mysql mysql  925 May 31 14:09 slow-log.log
[root@mysql5-7-18 ~]# service mysqld start
Starting MySQL..                                           [  OK  ]
[root@mysql5-7-18 ~]#