主从复制报1593错误的处理

由于模拟一主二从场景下主从切换的需要，在增加第二个从库时，启动第二个从库报如下错误：
mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State:
                  Master_Host: 10.16.24.107
                  Master_User: repl
                  Master_Port: 3376
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000068
          Read_Master_Log_Pos: 120
               Relay_Log_File: relay-bin.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: mysql-bin.000068
             Slave_IO_Running: No
            Slave_SQL_Running: Yes
              Replicate_Do_DB:
          Replicate_Ignore_DB:
           Replicate_Do_Table:
       Replicate_Ignore_Table:
      Replicate_Wild_Do_Table:
  Replicate_Wild_Ignore_Table:
                   Last_Errno: 0
                   Last_Error:
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 120
              Relay_Log_Space: 120
              Until_Condition: None
               Until_Log_File:
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File:
           Master_SSL_CA_Path:
              Master_SSL_Cert:
            Master_SSL_Cipher:
               Master_SSL_Key:
        Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 1593
                Last_IO_Error: Fatal error: The slave I/O thread stops because master and slave have equal MySQL server UUIDs; these UUIDs must be different for replication to work.
               Last_SQL_Errno: 0
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id: 1073376
                  Master_UUID:
             Master_Info_File: /data/mysql/mysql3376/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp: 160508 17:26:22
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set:
            Executed_Gtid_Set:
                Auto_Position: 0
1 row in set (0.00 sec)

上面错误发生在IO线程，错误码为1593，报错很明显是UUID与主库冲突:
查看主库的UUID：
(product)root@localhost [(none)]> show variables like 'server_uuid';

+---------------+--------------------------------------+
| Variable_name | Value                                |
+---------------+--------------------------------------+
| server_uuid   | 36af7e42-f4fc-11e5-8b08-0050568a0bcb |
+---------------+--------------------------------------+

查看从库的UUID:
mysql> show variables like 'server_uuid';
+---------------+--------------------------------------+
| Variable_name | Value                                |
+---------------+--------------------------------------+
| server_uuid   | 36af7e42-f4fc-11e5-8b08-0050568a0bcb |
+---------------+--------------------------------------+
1 row in set (0.00 sec)

上面比较UUID，确实完全相同，哦，原来第二个从库是主库冷备过来的，同时有将atuo.conf文件一同copy过来。
查看从库的auto.cnf文件内容如下：
[mysql@mvxl0784 data]$ cat auto.cnf
[auto]
server-uuid=36af7e42-f4fc-11e5-8b08-0050568a0bcb
[mysql@mvxl0784 data]$ pwd
/data/mysql/mysql3376/data

删除auto.cnf，并重启mysql后，查看auto.cnf文件，发现重新自动生成后内容不同了。
[mysql@mvxl0784 data]$ cat auto.cnf
[auto]
server-uuid=5548c382-1501-11e6-9bd4-0050568a3cbf

再启动slave后，查看从库状态，这时正常了。

mysql> start slave;
Query OK, 0 rows affected (0.00 sec)

mysql> show slave status\G
*************************** 1. row ***************************
               Slave_IO_State: Waiting for master to send event
                  Master_Host: 10.16.24.107
                  Master_User: repl
                  Master_Port: 3376
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000068
          Read_Master_Log_Pos: 120
               Relay_Log_File: relay-bin.000003
                Relay_Log_Pos: 283
        Relay_Master_Log_File: mysql-bin.000068
             Slave_IO_Running: Yes
            Slave_SQL_Running: Yes
              Replicate_Do_DB:
          Replicate_Ignore_DB:
           Replicate_Do_Table:
       Replicate_Ignore_Table:
      Replicate_Wild_Do_Table:
  Replicate_Wild_Ignore_Table:
                   Last_Errno: 0
                   Last_Error:
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 120
              Relay_Log_Space: 450
              Until_Condition: None
               Until_Log_File:
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File:
           Master_SSL_CA_Path:
              Master_SSL_Cert:
            Master_SSL_Cipher:
               Master_SSL_Key:
        Seconds_Behind_Master: 0
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error:
               Last_SQL_Errno: 0
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id: 1073376
                  Master_UUID: 36af7e42-f4fc-11e5-8b08-0050568a0bcb
             Master_Info_File: /apps/mysql/mysql3376/data/master.info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: Slave has read all relay log; waiting for the slave I/O thread to update it
           Master_Retry_Count: 86400
                  Master_Bind:
      Last_IO_Error_Timestamp:
     Last_SQL_Error_Timestamp:
               Master_SSL_Crl:
           Master_SSL_Crlpath:
           Retrieved_Gtid_Set:
            Executed_Gtid_Set:
                Auto_Position: 0
1 row in set (0.00 sec)