MySQL Master-Slave Replication

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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:
[B]vi   /etc/my.cnf[/B]


Add following lines

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


Restart mysql service

Code:
[B]service mysqld restart[/B]


Login to MYSQL with MYSQL root password

Code:
[B]mysql -u root -p[/B]

Grand Access to your slave server
Code:
[B]GRANT REPLICATION SLAVE ON *.* to ‘replication’@192.168.1.60 IDENTIFIED BY ‘yourpassword’;
mysql> FLUSH PRIVILEGES;
[/B]
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:
[B]mysql > SHOW MASTER STATUS;
+------------------+----------+--------------+------------------+
| File             | Position | Binlog_Do_DB | Binlog_Ignore_DB |
+------------------+----------+--------------+------------------+
| mysql-bin.000109 |      187 | mydb1         |                  |
+------------------+----------+--------------+------------------+[/B]

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



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.
 
Very well done and A+ for post formatting. That is a wealth of info in one place. What a challenge it would be to piece that together from google, i am sure many are going to appreciate this.
 
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