MySQL主从同步从库上Slave_IO_Running: Connecting问题

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一．在做主从同步时遇到的问题

数据库主从问题从库上Slave_IO_Running: Connecting  

在做mysql主从同步的时候有时候发现在从库上Slave_IO_Running: Connecting

二．解决办法通常是5个问题：

1.网络不通      #互ping机器ip，无丢包率正常访问，排除

2.密码不对      #MySQL重新授权远程用户登陆账号，重新设置密码，排除

3.pos不正确     #主服务器,登陆数据库重新查看起始偏移量show master status,排除

4.ID问题        

#ID的问题，在安装完mysql数据库的时候默认他们的server-id=1 但是在做主从同步的时候需要将ID号码设置不一样才行,查看数据库配置文件cat  /etc/my.cnf，文件写的不同，排除

5.防火墙策略  

查看防火墙策略，是否放通双方的服务端口 iptables -nL,最后发现 防火墙策略写了多端口防火墙策略的端口不生效，解决防火墙策略单独开放端口，暂停从服务的io读取stop slave;重新在从的数据库写入以下语句：

mysql> change master to

    -> master_host='192.168.137.36',             

    -> master_user='root',                 

    -> master_password='abc123',

    -> master_port=3307,

    -> master_log_file='mysql-bin.000001',

    -> master_log_pos=848;

Query OK, 0 rows affected, 2 warnings (0.05 sec)

mysql> start slave;

Query OK, 0 rows affected (0.02 sec)

mysql> show slave status\G

*************************** 1. row ***************************

               Slave_IO_State: Waiting for master to send event

                  Master_Host: 192.168.137.36

                  Master_User: root

                  Master_Port: 3307

                Connect_Retry: 60

              Master_Log_File: mysql-bin.000001

          Read_Master_Log_Pos: 1298

               Relay_Log_File: localhost-relay-bin.000002

                Relay_Log_Pos: 770

        Relay_Master_Log_File: mysql-bin.000001

             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: 1298

              Relay_Log_Space: 981

              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: 9

                  Master_UUID: ad899234-9c81-11e7-99bd-000c29af2bef

             Master_Info_File: /data/mysql_data1/master.info

                    SQL_Delay: 0

          SQL_Remaining_Delay: NULL

      Slave_SQL_Running_State: Slave has read all relay log; waiting for more updates

           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

         Replicate_Rewrite_DB:

                 Channel_Name:

           Master_TLS_Version:

1 row in set (0.00 sec)

注意：标注的俩个红色yes为正常。