@Mullen, I think your diagram does not answer the question on responses. @Sameer All nodes in DC2 will replay back to the co-ordinator in DC1. So if you have replication of DC1:3,DC2:3. A co-ordinator node will get 6 responses back if it is not in the replica set. Hope that answers your question.
On Tue, Feb 11, 2014 at 8:16 AM, Mullen, Robert <robert.mul...@pearson.com>wrote: > I had the same question a while back and put together this picture to help > me understand the flow of data for multi region deployments. Hope that it > helps. > > > On Mon, Feb 10, 2014 at 7:52 PM, Sameer Farooqui > <sam...@blueplastic.com>wrote: > >> Hi, >> >> I was hoping someone could clarify a point about multi-DC replication. >> >> Let's say I have 2 data centers configured with replication factor = 3 in >> each DC. >> >> My client app is sitting in DC 1 and is able to intelligently pick a >> coordinator that will also be a replica partner. >> >> So the client app sends a write with consistency for DC1 = Q and >> consistency for DC2 = Q to a coordinator node in DC1. >> >> That coordinator in DC1 forwards the write to 2 other nodes in DC1 and a >> coordinator in DC2. >> >> Is it correct that all 3 nodes in DC2 will respond back to the original >> coordinator in DC1? Or will the DC2 nodes respond back to the DC2 >> coordinator? >> >> Let's say one of the replica nodes in DC2 is down. Who will hold the hint >> for that node? The original coordinator in DC1 or the coordinator in DC2? >> > >
