Manage Multiple Data Center Clusters in cassandra

Question

I have set up Cassandra in 3 individual machines...say A,B,C , as per the documentation i did change the cassandra.yaml files of each machine like this

Machine A: listen_address = A's IP
   rpc_address = A's IP
   seeds = A's IP

Machine B: listen_address = B's IP
   rpc_address = B's IP
   seeds = A's IP

Machine C: listen_address = C's IP
   rpc_address = C's IP
   seeds = A's IP

Now if B,C any one of them are down I am not able to get records from A,which is expected to get,I am confusing in terms like node,datacenter...In above scenario I thought all are different data centers but when get ring info using nodetool;it shows them in same datacenter (datacenter1) what I need to know is correct setup so that it utilizes Cassandra efficiently

I created keyspace in each node like

create keyspace test
  with placement_strategy = 'SimpleStrategy'
  and strategy_options = {replication_factor : 1}
  and durable_writes = true;

I didnt used any consistentcy level...

Datacenter: datacenter1
==========
Replicas: 1

Address     Rack        Status State   Load            Owns                Token                                       
                                                                           849583800602241121                          
B's IP      rack1       Up     Normal  156.98 KB       95.39%              0                                           
C's IP      rack1       Up     Normal  130.3 KB        4.61%               849583800602241121

Patricia Patricia · Accepted Answer · 2013-07-10T18:14:07

Setting replication_factor to 1 means that there is only one copy of each row, on one node. It is possible that you're trying to ask for data that resides on the failed node, which explains why you aren't seeing anything returned.

To your earlier question, a data center is a geographically-grouped collection of individual nodes. Single or multiple data centers can be combined into a single cluster.

Manage Multiple Data Center Clusters in cassandra

2 Answers