I think the scenario you outlined is correct. The DES handles multiple
DCs poorly and the LOCAL_ONE hammer is the best bet.
On 01/31/2014 12:40 PM, Paulo Ricardo Motta Gomes wrote:
Hey,
When adding a new data center to our production C* datacenter using the
procedure described in [1], some of our application requests were returning
null/empty values. Rebuild was not complete in the new datacenter, so my
guess is that some requests were being directed to the brand new datacenter
which still didn't have the data.
Our Hector client was connected only to the original nodes, with
autoDiscoverHosts=false and we use ConsistencyLevel.ONE for reads. The
keyspace schema was already configured to use both data centers.
My question is: is it possible that the dynamic snitch is choosing the
nodes in the new (empty) datacenter when CL=ONE? In this case, it's
mandatory to use CL=LOCAL_ONE during bootstrap/rebuild of a new datacenter,
otherwise empty data might be returned, correct?
Cheers,
[1]
http://www.datastax.com/documentation/cassandra/1.2/webhelp/cassandra/operations/ops_add_dc_to_cluster_t.html
