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Re: slave to master




----- Original Message -----
> From: "Jason Mallory" <Jason.Mallory@xxxxxxxxxxx>
> Subject: RE: slave to master
>
> Master-master with load balancer would be best

That's a bit brief, isn't it? :-)

It's more than worth pointing out that your loadbalancer should not actually be loadbalancing the connections; master-master replication doesn't quite work the way you think it does in most scenarios.

You only want the loadbalancer for the automated failover; but it should never send requests to more than one master at any given time. Have it send everything to your primary master only; and when that host fails, have it send everything to the secondary master only, and never fail back automatically.

It's also worth noting that master-master is still not an officially supported replication topology. Regular master-slave also works fine with the above loadbalancer configuration; in that case you'll just treat the slave as the new primary after failover; and will manually reconfigure the broken master to be a slave (and adapt the loadbalancer config accordingly) as repair.

There does exist software that can do those reconfigurations by itself, MMM is one such example.

/Johan

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