Hector Cassandra Client Library User Mailing List ()

Jake Pearson | 21 Jun 2012 22:47

Cassandra ConsistencyLevel rules

We are having problems with understanding the different between the QUORUM and TWO ConsistencyLevel rules. We have a cluster defined with 3 nodes, a NetworkTopologyStrategy, and a SimpleSnitch. If the ConsistencyLevel is set to Quorum for writes, there is no problem. If we set the ConsistencyLevel to TWO for write, the write fails.

I believe in this case the both ConsistencyLevels require 2 nodes to write to but one fails and one succeeds. Any ideas?

thanks, Jake

headers

Nate McCall | 21 Jun 2012 22:57

Re: Cassandra ConsistencyLevel rules

In this case, CL.TWO would only fail if the replication factor was 1
(which means there is only one instance of your data, thus no
redundancy) whereas a quorum of 1 is 1.

On Thu, Jun 21, 2012 at 3:47 PM, Jake Pearson <jpearson@...> wrote:
> We are having problems with understanding the different between the QUORUM
> and TWO ConsistencyLevel rules.  We have a cluster defined with 3 nodes, a
> NetworkTopologyStrategy, and a SimpleSnitch.  If the ConsistencyLevel is set
> to Quorum for writes, there is no problem.  If we set the ConsistencyLevel
> to TWO for write, the write fails.
>
> I believe in this case the both ConsistencyLevels require 2 nodes to write
> to but one fails and one succeeds.  Any ideas?
>
> thanks, Jake

headers

Jake Pearson | 22 Jun 2012 16:10

Re: Cassandra ConsistencyLevel rules

Thanks, you were correct. I changed the replication factor and now I can write again.