On Tue, Jun 26, 2012 at 8:16 AM, Karthik N <karthik....@gmail.com> wrote:
> Since Cassandra optimizes and sends only one copy over the WAN, can I opt > in only for HH for WAN replication and avoid HH for the local quorum? > (since I know I have more copies) > > > I am not sure if I understand your question. In general I don't think you can selectively decide on HH. Besides HH should only be used when the outage is in mts, for longer outages using HH would only create memory pressure. > On Tuesday, June 26, 2012, Mohit Anchlia wrote: > >> >> On Tue, Jun 26, 2012 at 7:52 AM, Karthik N <karthik....@gmail.com> wrote: >> >>> My Cassandra ring spans two DCs. I use local quorum with replication >>> factor=3. I do a write in DC1 with local quorum. Data gets written to >>> multiple nodes in DC1. For the same write to propagate to DC2 only one >>> copy is sent from the coordinator node in DC1 to a coordinator node in >>> DC2 for optimizing traffic over the WAN (from what I have read in the >>> Cassandra documentation) >>> >>> Will a Wan hiccup result in a Hinted Handoff (HH) being created in >>> DC1's coordinator for DC2 to be delivered when the Wan link is up >>> again? >>> >> >> I have seen hinted handoff messages in the log files when the remote DC >> is unreachable. But this mechanism is only used for a the time defined in >> cassandra.yaml file. > > > > -- > Thanks, Karthik >
