MySQL master slave replication gives you two copies of your database: the “live” one and the backup one. You always write your data to your master and read from the master too, but you will always have an up-to-date copy on your slave.

Setting up the master Server

Make sure you have updated packages and MYSQL server isntalled in the server

#

Code:

yum update



#

Code:

yum install install mysql-server


Open the my.cnf file, which contains MYSQL database configuration

Code:

vi  /etc/my.cnf



Add following lines

Code:

[mysqld]
log-bin=mysql-bin
binlog-do-db=mydb1
server-id=1
innodb_flush_log_at_trx_commit=1
sync_binlog=1



Restart mysql service

Code:

service mysqld restart



Login to MYSQL with MYSQL root password

Code:

mysql -u root -p


Grand Access to your slave server

Code:

GRANT REPLICATION SLAVE ON *.* to ‘replication’@192.168.1.60 IDENTIFIED BY ‘yourpassword’;
mysql> FLUSH PRIVILEGES;




Replace the IP address (192.168.1.60)with your slave’s IPv4 address and replace ‘yourpassword’ with a strong password. Execute the query. It should say ‘Query OK’.

Check the current binary log file name (File) and current offset (Position) value using following command.

Code:

mysql > SHOW MASTER STATUS;
+------------------+----------+--------------+------------------+
| File            | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000109 |      187 | mydb1        |                  |
+------------------+----------+--------------+------------------+


Please note the filename (‘File’) and number (‘Position’). Remember these or write them down. You will use this to start replication on the slave.

Take a backup of database and copy it to slave mysql server.

Code:

mysqldump -u root -p mydb > mydb1.sql
# scp mydb1.sql 192.168.1.60:/opt/


Setup MySQL Slave Server

Make sure you have updated packages and MYSQL server isntalled in the server

Code:

# yum update
#yum install install mysql-server


Edit salve mysql configuration file and add following values under [mysqld] section.

Code:

[mysqld]
server-id=2
replicate-do-db=mydb1


Restart mysql service

Code:

service mysqld restart


Restore database backup taken from master server.

Code:

# mysql -u root -p mydb < mydb.sql


Setup option values on slave server using following command.

Code:

mysql>  CHANGE MASTER TO MASTER_HOST='192.168.1.20',
    -> MASTER_USER='replication',
    -> MASTER_PASSWORD='secretpassword',
    -> MASTER_LOG_FILE='mysql-bin.000109',
    -> MASTER_LOG_POS=187;


Finally start the slave thread

Code:

mysql> SLAVE START;


Check the status of slave server.

Code:

mysql> show slave status G

*************************** 1. row ***************************
              Slave_IO_State:
                  Master_Host: 192.168.1.60
                  Master_User: replication
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin.000109
          Read_Master_Log_Pos: 187
              Relay_Log_File: mysqld-relay-bin.000001
                Relay_Log_Pos: 4
        Relay_Master_Log_File: mysql-bin.000002
            Slave_IO_Running: No
            Slave_SQL_Running: No
              Replicate_Do_DB: mydb
          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: 187
              Relay_Log_Space: 187
              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:
  Replicate_Ignore_Server_Ids:
            Master_Server_Id: 1
1 row in set (0.00 sec)
mysql>


MySQL Master-slave Replication has been configured successfully on your system . You can test the same by creating a test datatabse in Master server, so it will automatically copied to slave server.

Source