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From Jonathan Colby <>
Subject Quorum and Datacenter loss
Date Sun, 12 Dec 2010 12:49:21 GMT
Hi cassandra experts -

We're planning a cassandra cluster across 2 datacenters
(datacenter-aware, random partitioning) with QUORUM consistency.

It seems to me that with 2 datacenters, if one datacenter is lost,
the  reads/writes to cassandra  will fail in the surviving datacenter
because of the N/2 + 1 distribution of replicas.  In other words, you
need more than half of the replicas to respond but in the case of a
datacenter loss you would only ever get 1/2 to respond at best.

Is my logic wrong here?  Is there a way to ensure the nodes in the
alive datacenter respond successfully if the second datacenter is
lost?  Anyone have experience with this kind of problem?


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