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From Jonathan Ellis <>
Subject Re: Consistency Levels and Replication with Down Nodes
Date Fri, 10 Jun 2011 18:18:31 GMT
On Fri, Jun 10, 2011 at 1:09 PM, AJ <> wrote:
> It says "all nodes".  Shouldn't it say "replication_factor nodes"?

My preferred phrasing would be "all replicas."

> I can understand this if the given row already exists from a previous write
> and one of the nodes that contains a replica is down.  But, what if this is
> the FIRST time creating this row and one of the nodes that it determines
> should store one of the replicas is down?  Will it choose another node to
> store the replica, or will it use hints to update the chosen down node when
> it comes back up?

ALL means ALL.

There is no such thing as "choosing another node to store a replica;"
replicas are determined by the partitioner and replication strategy
and cannot be changed at whim.  (How would you know where to find your
data, if replicas were not deterministic?)

> Generally speaking for any RF value and for the FIRST write of a particular
> row, does Cass select specific nodes to contain the replicas regardless of
> their availability, and use hints if some of them are unavailable?  Or, will
> it select another available node?

You should read

Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support

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