MySQL自定义了mysql.sock和data文件位置以后，重启如果my.cnf配置不完整会导致如下：
mysqldump: Got error: 2002: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111) when trying to connect
或者
mysqladmin: Got error: xxxx: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111) when trying to connect
或者
mysql: Got error: xxxx: Can't connect to local MySQL server through socket '/var/lib/mysql/mysql.sock' (111) when trying to connect
需要在my.cnf中告诉这些可执行文件sock在哪，：
[mysql] socket=/usr/local/web/data/mysql.sock [mysqladmin] socket=/usr/local/web/data/mysql.sock [mysqldump] socket=/usr/local/web/data/mysql.sock 重启MySql就可以了
