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From:Manuel Arostegui Date:January 18 2014 8:00am
Subject:Re: replication question replacing the master
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2014/1/17 Richard Reina <gatorreina@stripped>

> I have 3 relay MySQL database servers on my small office LAN backing up a
> master and 3 more machines backing up each relay (1 each). They are all
> replicating all databases and all tables. The master although running fine
> is almost eight years old. I'm thinking it's probably time to make one of
> the relays the master, but I've never done this before.
>
> I want the new master to have the IP address of the old master 192.168.0.1
> . To make the change I was going to take the master off the LAN and
> shutdown mysql on all the machines, change the IP address on the chosen
> relay to that of the master 192.168.0.1, then restart mysql on all the
> machines. I always refer to the machines by their IP addresses and never by
> their hostnames. Once I successfully make the change I was planning on
> making the old master a relay since it is still working fine.
>
> Will this plan work ok? Is there a better or easier way?
>
>
>
If the three machines are sync'ed and have consistent data I don't see the
need of stopping MySQL:

- Stop whatever writes to your current master
- Once you are completely sure there are no writes in your current master,
set it to read_only = ON
- In the slave which will become the master, get the logfile and current
position with: show master status;
 - Set the new IP in the new master


Using the position taken in the new master go to the slaves machines and:

stop slave; change master to master_host='IP',
master_log_file='whatever_file_name_you_got',
master_log_pos=whatever_number_you_got,
master_user='replication_or_whatever_you_have',
master_password='replication_or_whatever_you_have'; start slave;

- Set read_only = OFF in your new master
- Start your application so you can start getting writes again.

As soon as you get writes if you do a "show master status;" in the new
master you should see the position going forward.

I see that faster than any other thing.

Hope this helps
Manuel.

Thread
replication question replacing the masterRichard Reina17 Jan 2014
  • Re: replication question replacing the masterReindl Harald17 Jan 2014
  • Re: replication question replacing the masterManuel Arostegui18 Jan 2014
    • Re: replication question replacing the masterRichard Reina18 Jan 2014