In other words, if N-Way supports two masters writing while MM does not, how can it not have a different configuration?
It has nothing to do with configuration of MMR, which I think is the point you're missing. It has purely to do with configuring it so only one master ever takes writes at a given time. With writes only ever going to one master, you have a 100% guarantee you'll never get a conflict between two masters. Which you essentially get with delta-syncrepl MMR anyway.
Exactly, I definitely missed that. The Admin Guide alludes to these being distinct configurations by the way they're bulleted out but the difference is actually in the architecture outside of OpenLDAP. Thanks for that clarification.
What I've designed is a two-node cluster each running a proxy that talks to the local backend over IPC and fails over to the other node over TCP if via the meta backend. This becomes Nway because clients are being distributed via DNS. (The proxies fail between the nodes, the backend slapd's do not.)
John