> · If node ‘X ‘ in DC1 which is a ‘replica’ node is down and a write > comes with CL =1 to DC1, the co-ordinator node will write the hint and also > the data will be written to the other ‘replica’ node in DC2 ? Is this correct > ? Writes always go to all UP replicas. So yes.
> · If yes, then when we try to do a ‘read’ of this data with CL = > ‘local_quorum’ from DC1, it will fail (since the data was written as a hint) > and we will need to read it from the other DC ? It depends on your definition of fail. If node X is still down a read at LOCAL_QUORUM will fail to start and raise an UnavailableException. If node X is up, but the hints have not been delivered, the read will proceed and return the value before the write in step 1 above (including no value) Cheers ----------------- Aaron Morton Freelance Cassandra Consultant New Zealand @aaronmorton http://www.thelastpickle.com On 9/05/2013, at 4:38 PM, Kanwar Sangha <kan...@mavenir.com> wrote: > Is this correct guys ? > > From: Kanwar Sangha [mailto:kan...@mavenir.com] > Sent: 07 May 2013 14:07 > To: user@cassandra.apache.org > Subject: HintedHandoff > > Hi -I had a question on hinted-handoff. We have 2 DCs configured with > overall RF = 2 (DC1:1, DC2:1) and 4 nodes in each DC (total – 8 nodes across > 2 DCs) > > Now we do a write with CL = ONE and Hinted Handoff enabled. > > · If node ‘X ‘ in DC1 which is a ‘replica’ node is down and a write > comes with CL =1 to DC1, the co-ordinator node will write the hint and also > the data will be written to the other ‘replica’ node in DC2 ? Is this correct > ? > · If yes, then when we try to do a ‘read’ of this data with CL = > ‘local_quorum’ from DC1, it will fail (since the data was written as a hint) > and we will need to read it from the other DC ? > > Thanks, > Kanwar
