I'm new at CouchDB. I want to configure replication but don't understand how zones works. I can define clusters at both cites without zones next add db1 (PUT http://city1/db1?n=2&q=3) and finally add replication (for example: source: db1 at city1 - target new database at city2). I do not understand the advantages of defining zones at nodes and zone at db (PUT http://city1/db1?zone=zone1).
I am open to suggestions how should I proper define zones at clusters and define replication after that.