mysql主从赋值，从机验证报错：ERROR 3021(HY000):this operation cannot be performed with a running salve io thread

原因：

mysql从机上已经进行过绑定了，如果继续绑定需要先进行重置。

解决办法

1、停止已经启动的绑定

stop slave

2、重置绑定

reset master

3、执行复制主机命令

change master to master_host = '192.168.12.1' master_user = 'slave' ,master_password ='123456' ,master_log_file = 'mysql-bin.000004',master_log_pos = '881'

4、发现此时已经不报错
5、启动复制

start slave