Re: add slave to existing master-master replication

[Teri LeBlanc]

Hi Rick,

Thanks very much for your comments. We hope never to have to promote either slave to master, but in the event of complete failure of datacenter1 it could happen. (there are also failover application servers in datacenter2)

That is why I wonder about the auto_increment_increment & offset.

The original servers were not built with any expansion in mind. I was therefore thinking that if I went with the 3rd topology (i.e. datacenter1 M1---> datacenter2 S1 and datacenter1 M2----> datacenter2 S2) and if I set the slave settings same as the corresponding master, the data written during the "disaster" will at least be consistent with what would have been written on the masters. Then if masters come back and we need to restore the data it will "match" what would have been written to the masters.

Does that make any sense?

Thanks, Teri