Mysql – Will thesql_secure_install script block master updates to slave

There's a stack of system related questions here. We don't know what the hardware looks like for your master or slave. Maybe you're lacking RAM on the slave, or any number of other differences.

The master is probably receiving bursts of updates in parallel from many client connections, and for whatever reason, the slave can't keep up since all replication is done in serial.

If you have a lot of InnoDB activity on the master, you can probably disable InnoDB on the slave and gain some speed that way. That option and a few others are given here:

16.4.4.7: How can I use replication to improve performance of my system? http://dev.mysql.com/doc/refman/5.0/en/replication-faq.html#qandaitem-16-4-4-1-7

Or there could be configuration tweaks in my.cnf that could help you. I'd start by looking at your memory usage on the slave, and looking up buffer and memory related options for innodb and/or myisam depending on which of those engines you're using (or others).

You can also look through your binlogs with the mysqlbinlog tool to see what database and tables have the most activity. Then start working with your application developers and start chipping away at the problem.

Also check your mysqld error log on the slave. There might be clues in there.

Going by your question, I will like to review what I believe you did thus far:

• You stopped mysql on the Master
• You copied Master's /var/lib/mysql to the Slave's /var/lib/mysql
• I surmise the binlogs on the Master were copied as well

Look at the Slave's last binlog. From the question, it should be

• mydbm1-bin.008524
• Filesize 1330529

Believe it or not, you have to do a few things:

1) On the Master, create a replication user like this:

GRANT REPLICATION SLAVE,REPLICATION CLIENT
ON *.* TO replicator@'%'
IDENTIFIED BY 'r3plic4t0R';

2) Make /var/lib/mysql on the Slave owned by mysql user

chown -R mysql:mysql /var/lib/mysql

3) Make sure Master's server_id is explicitly set in my.cnf

[mysqld]
server_id = 1

4) Make sure Slave's server_id is explicitly set in my.cnf

[mysqld]
server_id = 2

5) Startup mysql on the Slave

service mysql start

6) Setup replication by running this on the Slave

CHANGE MASTER TO
MASTER_HOST='IPAddressOfMaster',
MASTER_PORT=3306,
MASTER_USER='replicator',
MASTER_PASSWORD='r3plic4t0R',
MASTER_LOG_FILE='mydbm1-bin.008524',
MASTER_LOG_POS=1330529;
START SLAVE;
SELECT SLEEP(5);
SHOW SLAVE STATUS\G

You will see something like this:

mysql> show slave status\G
*************************** 1. row ***************************
             Slave_IO_State: Waiting for master to send event
                Master_Host: 10.48.20.253
                Master_User: replicant
                Master_Port: 3306
              Connect_Retry: 60
            Master_Log_File: mysql-bin.000254
        Read_Master_Log_Pos: 858190247
             Relay_Log_File: relay-bin.066069
              Relay_Log_Pos: 873918
      Relay_Master_Log_File: mysql-bin.000254
           Slave_IO_Running: Yes
          Slave_SQL_Running: Yes
            Replicate_Do_DB:
        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: 858190247
            Relay_Log_Space: 873772
            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: 0
1 row in set (0.00 sec)

If Slave_IO_Running and Slave_SQL_Running are both Yes, CONGRATULATIONS !!!

I already answered a post back on Feb 06, 2012 ( How to setup replication(Master/slave) in MySQL 5.5.20? ) with essentially the same steps.

I wanted to add additional posts I made for setting up Circular Replication should you decide to setup the two DB servers as Master/Master

• Sep 24, 2012 : Setting up MySQL circular replication in existing replication topology?
• May 07, 2012 : Setting Circular Replication in mysql