http://www.datastax.com/support-forums/topic/replication-in-two-data-center-configuration Software, Support, and Training for Apache Cassandra en-US Wed, 19 Jun 2013 13:07:01 +0000 http://bbpress.org/?v=1.0.3 q http://www.datastax.com/support-forums/search.php http://www.datastax.com/support-forums/topic/replication-in-two-data-center-configuration#post-1453 Thu, 29 Mar 2012 00:39:05 +0000 Anonymous 1453@http://www.datastax.com/support-forums/ <p>Appreciate the responses. We'll probably end up going with a 2 and 2 setup after we get a few more nodes up, thanks!! </p> http://www.datastax.com/support-forums/topic/replication-in-two-data-center-configuration#post-1364 Tue, 13 Mar 2012 23:38:00 +0000 jbellis 1364@http://www.datastax.com/support-forums/ <p>"Two copies local, one copy remote" is not supported, because then the replicas would have to change depending on which DC you're querying from.</p> <p>OldNetworkTopologyStrategy would allow 3 total replicas, where sometimes the 3rd is in DC1, and other times in DC2 (deterministically). Or you could just leave it as just two replicas, or four as Jackson suggested. </p> http://www.datastax.com/support-forums/topic/replication-in-two-data-center-configuration#post-1363 Tue, 13 Mar 2012 23:14:07 +0000 jackson@datastax.com 1363@http://www.datastax.com/support-forums/ <p>Hello Alvin,</p> <p>When setting up strategy option as "{DC1:2,DC2:1}", Cassandra will place 2 replicas in DC1 and 1 replica in DC2, as you have observed. This is the expected behavior.</p> <p>All replicas are the same in Cassandra. There is no concept of replicating an extra copy within the "local datacenter", and replicate once in the "remote". You could do "{DC1:2, DC2:2}" such that each datacenter has 2 replicas for every write it receives.</p> <p>Regards,<br /> Jackson </p> http://www.datastax.com/support-forums/topic/replication-in-two-data-center-configuration#post-1361 Tue, 13 Mar 2012 18:39:54 +0000 Anonymous 1361@http://www.datastax.com/support-forums/ <p>Any ideas? </p> http://www.datastax.com/support-forums/topic/replication-in-two-data-center-configuration#post-1333 Wed, 07 Mar 2012 21:38:09 +0000 Anonymous 1333@http://www.datastax.com/support-forums/ <p>Hi all, thanks in advance for your help! :)</p> <p>Our team has a two data center configuration. We have a 6 node cluster with 3 nodes on each site. We want to have a replication factor of 3, replicating once to the local site and once cross site. Currently, we are using strategy_options={DC1:2,DC2:1}; for our keyspace, but notice that DC1 will always have two replicas while DC2 will always only have one replica, regardless of node.</p> <p>What is the suggested way to specify our strategy so that each node will replicate once locally and once cross site?</p> <p>Thank you!!<br /> Alvin </p>