Not necessarily. It depends on how the token ranges for the vNodes are assigned to them. For example take a look at this diagram http://docs.datastax.com/en/archived/cassandra/2.0/cassandra/architecture/architectureDataDistributeDistribute_c.html
In the vNode part of the diagram, you will see that Loss of Node 3 and Node 6, will still not have any effect on Token Range A. But yes if you lose two nodes that both have Token Range A assigned to them (Say Node 1 and Node 2), you will have unavailability with your specified configuration. You can sort of circumvent this by using the DataStax Java Driver and having the client recognize a degraded cluster and operate temporarily in downgraded consistency mode http://docs.datastax.com/en/latest-java-driver-api/com/datastax/driver/core/policies/DowngradingConsistencyRetryPolicy.html - Rahul On Mon, Jan 15, 2018 at 10:04 AM, Kyrylo Lebediev <kyrylo_lebed...@epam.com> wrote: > Hi, > > > Let's say we have a C* cluster with following parameters: > > - 50 nodes in the cluster > > - RF=3 > > - vnodes=256 per node > > - CL for some queries = QUORUM > > - endpoint_snitch = SimpleSnitch > > > Is it correct that 2 any nodes down will cause unavailability of a > keyrange at CL=QUORUM? > > > Regards, > > Kyrill >
