今天在配置mysql replication的时候，修改完my.cnf文件，然后重启mysql service ,当执行下列命名的时候报错：
change master to master_host='127.0.0.1',
master_user='usertest',master_password='usertest', master_log_file='mysql-bin-000002', master_log_pos=8;
ERROR 1201 (HY000): Could not initialize master info structure; more error messages can be found in the MySQL error log
check错误日志文件 mysqld.log ,发现有如下错误：
140123 12:48:18 [ERROR] Error reading master configuration
140123 12:48:18 [ERROR] Failed to initialize the master info structure
后来检查发现在mysql数据库文件夹下面有个 空的master.info 文件（有时候还有个空的relay-log.info），问题在这里。
解决办法：
method 1 :
mysql> stop slave ;
mysql> reset salve ;
then change master
mysql> change master to master_host='127.0.0.1', master_user='usertest', master_pass
word='usertest', master_log_file='mysql-bin-000002', master_log_pos=8;
Query OK, 0 rows affected (0.11 sec)
method 2 :
rm -f /var/lib/mysql/master.info
then
mysql> change master to master_host='127.0.0.1', master_user='usertest', master_pass
word='usertest', master_log_file='mysql-bin-000002', master_log_pos=12;
Query OK, 0 rows affected (0.11 sec)
最后检查MySQL主从同步是否正常
mysql> start slave ;
Query OK, 0 rows affected (0.01 sec)
mysql> show slave status \G
*************************** 1. row ***************************
Slave_IO_State: Waiting for master to send event
Master_Host: 127.0.0.1
Master_User: korea_slave
Master_Port: 3306
Connect_Retry: 60
Master_Log_File: bin-update-log.000009
Read_Master_Log_Pos: 1551
Relay_Log_File: mysqld-relay-bin.000002
Relay_Log_Pos: 1702
Relay_Master_Log_File: bin-update-log.000009
Slave_IO_Running: Yes
Slave_SQL_Running: Yes
Replicate_Do_DB: tkglobal,tktest
Replicate_Ignore_DB: local
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: 1551
Relay_Log_Space: 1859
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: 1260119
1 row in set (0.00 sec)
