mysql主从同步从库上Slave_IO_Running: Connecting问题
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。
