MySQL双主热备问题处理

1. Slave_IO_Running: No

mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State:
Master_Host: 192.16.10.21
Master_User: cahms
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 20398
Relay_Log_File: mysqld-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File: mysql-bin.000003
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: 20398
Relay_Log_Space: 106
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 ids; these ids must be different for replication to
work (or the --replicate-same-server-id option must be used on slave but
this does not always make sense; please check the manual before using
it).
Last_SQL_Errno: 0
Last_SQL_Error:
1 row in set (0.00 sec)

(1) master and slave have equal MySQL server ids

【解决的方法】

改动/etc/my.cnf 下的server-id的值。确保master和slave的server-id不一样就可以；

(2) Error reading packet from server:

Access denied; you need the REPLICATION SLAVE privilege for this operation ( server_errno=1227)

【解决的方法】主服务器给的复制权限不够。又一次赋予权限。

> grant replication slave on *.* to 'uname'@'对端ip' identified by 'password'。
> flush privileges。

== e.g ==

> grant replication slave on *.* to 'root'@'192.16.10.21'
identified by 'root';
> grant replication slave on *.* to 'root'@'192.16.10.23'
identified by 'root';

2. Slave_IO_State:

Waiting to reconnect after a failed master event read
mysql> show slave status\G
*************************** 1. row ***************************
Slave_IO_State: Waiting to reconnect after a failed master event read
Master_Host: 192.16.10.231
Master_User: cahms
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: mysql-bin.000003
Read_Master_Log_Pos: 106
Relay_Log_File: mysqld-relay-bin.000001
Relay_Log_Pos: 4
Relay_Master_Log_File: mysql-bin.000003
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: 106
Relay_Log_Space: 106
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: 0
Last_IO_Error:
Last_SQL_Errno: 0
Last_SQL_Error:
1 row in set (0.00 sec)

【解决的方法】

> grant replication slave on *.* to 'root'@'192.16.10.228'
identified by 'root';

> grant replication slave on *.* to 'root'@'192.16.10.231'
identified by 'root';

> flush privileges;

3.Another MySQL daemon already running with the same unix socket.

原因多个Mysql进程使用了同一个socket。 两个方法解决：

第一个是马上关机 使用命令 shutdown -h now 关机，关机后在启动。进程就停止了。

第二个直接把mysql.sock文件改名就可以。也能够删除，推荐改名。

然后就能够启动mysql了。

以下是国外原文

# shutdown -h now

This will stop the running services before powering down the machine.

Based on Centos, an additional method for getting it back up again when you run into this problem is to move mysql.sock:

# mv /var/lib/mysql/mysql.sock /var/lib/mysql/mysql.sock.bak

# service mysqld start

Restarting the service creates a new entry called mqsql.sock