set-up-a-mysql-slave-using-mysqldump-to-get-the-in

f you are dumping a mysql database that has a mixture of InnoDB and MyISAM and you have scheduled downtime:

mysqldump -u... -p... --master-data=1 --single-transaction --flush-privileges --routines --triggers --all-databases > /root/mydata.sql

Since --opt is enabled by default, the following options are already enabled

• --add-drop-table
• --add-locks
• --create-options
• --quick
• --lock-tables
• --set-charset
• --disable-keys

If you are concerned about InnoDB/MyISAM together in the mysqldump and you want the database placed in a read-only state, try putting a read lock across all tables manually.

MYSQL_CONN="-hhostip -uusername -ppassword" mysql ${MYSQL_CONN} -A -e"FLUSH TABLES WITH READ LOCK; SELECT SLEEP(86400)" & SEARCHING_FOR_SLEEP=0 while [ ${SEARCHING_FOR_SLEEP} -eq 0 ] do
    sleep 3 SEARCHING_FOR_SLEEP=`${MYSQL} ${MYSQL_CONN} -A -e"SHOW PROCESSLIST;" | grep -c "SELECT SLEEP(86400)"` done
sleep 1 SLEEP_ID=`mysql ${MYSQL_CONN} -A -e"SHOW PROCESSLIST;" | grep "SELECT SLEEP(86400)" | awk '{print $1}'` mysqldump ${MYSQL_CONN} --master-data=2 --single-transaction --flush-privileges --routines --triggers --all-databases > /root/mydata.sql mysql ${MYSQL_CONN} -A -e"KILL ${SLEEP_ID}"

The reason this is better to do is that --single-transaction does not protect MyISAM from changing during the dump.

Before launching the mysqldump, make sure binary logging is enabled on the master. If it is not, do the following:

Step 01) Add this to /etc/my.cnf on the master

[mysqld] log-bin=mysql-bin

Step 02) service mysql restart

This will enable binary logging on the master.

On the new slave, you can run the following command:

CHANGE MASTER TO MASTER_HOST='IP of the master', MASTER_PORT=3306, MASTER_USER='whatever_username', MASTER_PASSWORD='whatever_password', MASTER_LOG_FILE='mysql-bin.000001', MASTER_LOG_POS=107;

Make sure the rep_username exists in the master. If it does not, run this command on the master:

GRANT SELECT, REPLICATION SLAVE, REPLICATION CLIENT ON *.* TO 'whatever_username'@'%' IDENTIFIED BY 'whatever_password';

Then do the mysqldump to /root/mydata.sql.

Move the /root/mydata.sql from the master to the slave.

Next, execute in the mysql client this command on the slave:

source /root/mydata.sql

This will load mysqldump in the slave and the set the correct log file and log position in /var/lib/mysql/master.info.

Finally, run START SLAVE; on the slave and mysql replication should get going.

Run SHOW SLAVE STATUS\G to check replication status.

Give it a Try !!!