incubator-cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Jonathan Ellis <jbel...@gmail.com>
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 <aj@dude.podzone.net> 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 http://wiki.apache.org/cassandra/Operations.

-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of DataStax, the source for professional Cassandra support
http://www.datastax.com

Mime
View raw message