MySQL的SLAVE狀态：Slave_IO_Running: NO和Slave_SQL_Running: No

show slave status\G;

發現:　Slave_IO_Running: NO

        　Slave_SQL_Running: No

也不能啟動slave

mysql> slave start;

ERROR 1201 (HY000): Could not initialize master info structure; more error messagescan be found in the MySQL error log

打開/usr/local/mysql/datat/.err錯誤日志檔案：

130416 14:03:54 [ERROR] Failed to open the relay log './localhost-relay-bin.000002' (relay_log_pos 253)

130416 14:03:54 [ERROR] Could not find target log during relay log initialization

130416 14:03:54 [ERROR] Failed to initialize the master info structure

解決方法：

删除所有檔案名包含relay的檔案，relay-log.info，relay-bin.index，relay-bin.xxxxxx檔案。

1）關閉mysql, 

#/etc/init.d/mysqld stop

2）删除relay檔案

#rm -f *relay*

3）登入mysql，啟動slave

#mysql -uroot  -p

mysql>slave start

mysql>show slave status\G  

引起的原因：修改了centos的主機名，找不到relay-bin.index檔案，導緻二進制日志為空。