設定可以觀看 mysql 的 error log 檔案  

mkdir /var/log/mysql
chown mysql:mysql /var/log/mysql
chmod 750 /var/log/mysql

The best choice is to define the error log, in both the [mysqld_safe] and [mysqld] section of your servers my.cnf
[mysqld_safe]
     log-error=/var/log/mysql/error.log
[mysqld]
     log-error=/var/log/mysql/error.log

轉貼自:http://ronaldbradford.com/blog/monitoring-mysql-the-error-log-2009-09-16/