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Date: Sun, 12 Dec 2010 13:49:21 +0100
Message-ID: <AANLkTimTyk4XVbDWs8nH+nbKOp7+9z28YMEVF1Rj2Ou5@mail.gmail.com>
Subject: Quorum and Datacenter loss
From: Jonathan Colby <jonathan.colby@gmail.com>
To: user@cassandra.apache.org
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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?

Thanks.