Matwey V. Kornilov wrote:

Hello,

...

From Administrator's guide, it is not completely clear what is the

internal difference between mirror mode and n-way multi master.

There is no internal difference. The difference is in how clients use the servers. In mirrormode you arrange for all write ops to only go to one provider.

1. Can 2-way multi master configuration exist? If so, what should be

difference in slapd.conf between mirror mode and 2-way multi master?

There is no difference in slapd configuration.

What is the difference in syncrepl behaviour? Or all difference is that external proxy/balancer assumed when mirror mode is meant?

All difference is in the external proxy.

2. Is there quorum based consensus when 3-way multi master is used? If

not, how is the conflict resolution performed?

No quorums needed. Conflict resolution is based on CSNs. In general, last writer wins.