If you use a chain of masters, you can accomplish the same effect:

Master1->Master2->Master->3->Slave

However I don't recommend this since the more links you have in a replication 
chain, the easier it is to break it in a way that's very not-fun to deal with.


-----Original Message-----
From: Rolando Edwards [mailto:redwa...@logicworks.net]
Sent: Wednesday, November 24, 2010 6:53 AM
To: Machiel Richards; mysql mailing list
Subject: RE: Another replication question

MySQL, by design, cannot do that.

A DB Server can be Master to Multiple Slaves
Think of the CHANGE MASTER TO command.
Its internal design cannot accommodate reading from more than one set of relay 
logs.

You could attempt something convoluted, like
1) STOP SLAVE;
2) CHANGE MASTER TO <Master 1>
3) START SLAVE;
4) Read and process some binary log transactions, wait till you are zero sec 
behind master
5) STOP SLAVE;
6) CHANGE MASTER TO <Master 2>
7) START SLAVE;
8) Read some process binary log transactions, wait till you are zero sec behind 
master
9) Repeat from step 1

Make sure Each Master is updating only one specific set of databases, mutual 
exclusive from other Masters
Make sure you properly record the log file and log position from each master

I would never try this under normal circumstances.

I think this was described in the "High Performance MySQL" book
http://www.amazon.com/dp/0596101716?tag=xaprb-20


Rolando A. Edwards
MySQL DBA (CMDBA)

155 Avenue of the Americas, Fifth Floor
New York, NY 10013
212-625-5307 (Work)
201-660-3221 (Cell)
AIM & Skype : RolandoLogicWorx
redwa...@logicworks.net
http://www.linkedin.com/in/rolandoedwards


-----Original Message-----
From: Machiel Richards [mailto:machi...@rdc.co.za]
Sent: Wednesday, November 24, 2010 7:20 AM
To: mysql mailing list
Subject: Another replication question

Hi All

    I am back once again with another replication question (maybe this
can also be handled by MMM but not sure) this time for a different
client.

    We are trying to find out how to setup 3 different masters to
replicate to a single slave server (without the need to have 3 different
instances running on the slave machine).

        Does anybody have any ideas?

        Any ideas will be greatly appreciated.

Regards
Machiel

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