ERROR 3021 (HY000): This operation cannot be performed with a running slave io thread; run STOP SLAVE IO_THREAD FOR CHANNEL '' first.

mysql 主從服務，停止從服務器從機器上執行開始復制命令出現錯誤

解決故障

io線程開啟中無法對從服務器進行修改，因此我們需要關閉io線程

mysql> STOP SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)
mysql> change master to master_host='192.168.0.99',master_port=3307,master_user='copy',master_password='copy',master_log_file='mysql-bin.000001',master_log_pos=154;
Query OK, 0 rows affected, 2 warnings (0.00 sec)
mysql> START SLAVE IO_THREAD;
Query OK, 0 rows affected (0.00 sec)