Re: Multi master to single slave replication

[Tom Krouper]

The only way I've found to do this is to create a convoluted script to
1. Stop replication on the slave.
2. Record the master's file and pos from show slave status.
3. Do a change master to the "other" master.
4. Let it catch up for a set time.
5. repeat.

There are many issues with this solution. The first being if you don't catch up by the set time in step 4 you end up having to verify that the exec and read pos in the show slave status command match or that you get the right one. Also if replication does get messed up you have to go through the error logs to find out where you need to catch up from which can be a huge pain if you are changing masters a lot.

I only did this in a situation where we were updating two entirely different databases. I turned on the %ignore_db stuff to avoid messing up mysql.%.

It has many issues and I'd love a better solution. If you find one, please let me know.