Thanks Rob that helps !
On Fri, Oct 25, 2013 at 7:34 PM, Robert Coli <rc...@eventbrite.com> wrote: > On Fri, Oct 25, 2013 at 2:47 PM, srmore <comom...@gmail.com> wrote: > >> I don't know whether this is possible but was just curious, can you query >> for the data in the remote datacenter with a CL.ONE ? >> > > A coordinator at CL.ONE picks which replica(s) to query based in large > part on the dynamic snitch. If your remote data center has a lower badness > score from the perspective of the dynamic snitch, a CL.ONE request might go > there. > > 1.2.11 adds [1] a LOCAL_ONE consistencylevel which does the opposite of > what you are asking, restricting CL.ONE from going cross-DC. > > >> There could be a case where one might not have a QUORUM and would like to >> read the most recent data which includes the data from the other >> datacenter. AFAIK to reliably read the data from other datacenter we only >> have CL.EACH_QUORUM. >> > > Using CL.QUORUM requires a QUORUM number of responses, it does not care > from which data center those responses come. > > >> Also, is there a way one can control how frequently the data is >> replicated across the datacenters ? >> > > Data centers don't really exist in this context [2], so your question is > "can one control how frequently data is replicated between replicas" and > the answer is "no." All replication always goes to every replica. > > =Rob > [1] https://issues.apache.org/jira/browse/CASSANDRA-6202 > [2] this is slightly glib/reductive/inaccurate, but accurate enough for > the purposes of this response. >
