What would be the best approach for CouchDB replication in the following setup:

A1 and A2 are two CouchDB servers in one DC. They both pull data from each other, although only one is actively used, the other is just a stand by in case of a failure of the first one.

B1 and B2 are similarly set up in terms of replication and are located in a different DC.

What's the best way of achieving A <-> B replication?

I see two options here:

**Option 1:**

- A1 pulls from B1 and B2
- A2 pulls from B1 and B2
- B1 pulls from A1 and A2
B2 pulls from A1 and A2

A1 pulls from A2

- A2 pulls from A1
- B1 pulls from B2
- B2 pulls from B1

**Option 2:**

- A1 pulls from B1
- A2 pulls from B2
- B1 pulls from A1
B2 pulls from A2

A1 pulls from A2

- A2 pulls from A1
- B1 pulls from B2
- B2 pulls from B1

IMHO Option 2 is sufficient and covers all bases for the HA setup, ie one way or the other no singe failure would prevent data from being replicated to all 4 DB instances.

There's not much data in there, we're talking about 50-100MB of data max.

Comments welcome. Thanks!