Hello, I have a testing cluster with: A (dc1), B (dc1), C(dc2), D(dc2). The replication factor is 2 so I assume each DC will have a complete copy of the data. Also I'm using PropertyFileEndPointSnitch with rack.properties for the dc and rack settings.
So, what's the steps to add another datacenter and increase replication factor to 3 to ensure that dc3 will also get a complete copy of the data? Meaning each of these 3 dc will have a complete copy of the data and they keep synchronize with each other with new changes. What I'm guessing is: 1) Increase replication factor of A/B/C/D to 3, modify their rack.properties to include E(dc3) and F(dc3) then restart them one by one. At this point E and F haven't been started yet. 2) Bootstrap E and F (both from dc3) to join the cluster. in this case, will cassandra automatically put the 3rd replica to E and F? Thanks, -Weijun P.S here what the cassandra document says about dc replication but I'm not sure what will happen when you join nodes from the 3rd dc. - RackAwareStrategy: replica 2 is is placed in the first node along the ring the belongs in *another* data center than the first; the remaining N-2 replicas, if any, are placed on the first nodes along the ring in the *same* rack as the first
