_MySQL master slave replication
_
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

yum update

yum install install mysql-server

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

vi /etc/my.cnf

Add following lines

**[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

service mysqld restart

Login to MYSQL with MYSQL root password

mysql -u root -p

Grand Access to your slave server
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.

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.
** 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

**# yum update

yum install install mysql-server**

Edit salve mysql configuration file and add following values under [mysqld] section.
[mysqld]
server-id=2
replicate-do-db=mydb1

Restart mysql service
service mysqld restart

Restore database backup taken from master server.
# mysql -u root -p mydb < mydb.sql

Setup option values on slave server using following command.
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
mysql> SLAVE START;

Check the status of slave server.
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.