Specify the configuration instance of mysql database server master slave synchronization under linux

1. The concept:
1. Database synchronization (master and slave synchronization -- master database writes data to slave server at the same time)
(2) database synchronization (master master synchronization -- two database servers write data to each other)

2. For example
Database server (A) master database IP: 192.168.1.134
Database server (B) master database IP: 192.168.1.138
The user name of the synchronization between the two servers is: bravedu password: brave123

1. Master database operation Settings (A) :
Create the user IP address (not native IP) to which the synchronous user name is allowed to connect

grant replication slave on *.* to 'bravedu'@'192.168.1.%' identified by 'brave123';
flush privileges;

Change the mysql configuration file

[mysqld]  
server-id = 1  
log-bin=/www/mysql/binlog/binlog ( The path should be set according to your installation )
binlog-do-db = dbname ( The database name to synchronize ) 
binlog-ignore-db=mysql

Restart the mysql server

View the master database synchronization status

mysql>flush tables with read lock;  
mysql>show master status\G
*************************** 1. row ***************************
  File: mysql-bin.000001    ( Note here   This is used when setting up the slave server )
  Position: 106   ( Note that this is used when setting up the slave server )
  Binlog_Do_DB: dbname
  Binlog_Ignore_DB: mysql
  1 row in set (0.00 sec)

mysql>unlock tables;
******* The primary server has been set up at the current location ***********

2. Operation Settings from the database (B) :

Create a synchronized user name

grant replication slave on *.* to 'bravedu'@'192.168.1.%' identified by 'brave123';
flush privileges;

Change the mysql configuration file

[mysqld]  
server-id = 2  
log-bin=/www/mysql/binlog/binlog ( The path should be set according to your installation )
binlog-do-db = dbname ( The database name to synchronize ) 
binlog-ignore-db= mysql,information_schema

Restart the mysql server

(3) specify master and slave database server synchronization instructions
Note: the IP, username, password,log_file,log_post of the IP primary server are all unified with the primary server 1
Perhaps this operation requires unlocking the table, stopping the database state, and starting it after running

mysql > stop  slave;
mysql > change master to master_host='192.168.1.134', master_user='bravedu', master_password='brave123', master_log_file='mysql-bin.000001', master_log_pos=106; 
mysql > start slave;
mysql > unlock tables;

Check the synchronization state of the main database will come out a lot of information but mainly look at the two states on the line if they are yes

mysql>show slave status\G;
Slave_IO_Running: Yes
Slave_SQL_Running: Yes

At this point, the master-slave database synchronization configuration is complete.