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From Eric tamme <eta...@gmail.com>
Subject Replica data distributing between racks
Date Mon, 02 May 2011 18:40:32 GMT
I am experiencing an issue where replication is not being distributed
between racks when using PropertyFileSnitch in conjunction with
NetworkTopologyStrategy.

I am running 0.7.3 from a tar.gz on  cassandra.apache.org

I have 4 nodes, 2 data centers, and 2 racks in each data center.  Each
rack has 1 node.

I have even token distribution so that each node gets 25%:

0
425352958651173079329218259289
71026432
85070591730234615865843651857942052864
127605887595351923798765477786913079296

My cassandra-topology.properties is as follows:

# Cassandra Node IP=Data Center:Rack
ffff\:0\:ffff\:eeee\:\:fffe=NY1:RAC1
ffff\:0\:ffff\:eeee\:\:ffff=NY1:RAC2

ffff\:0\:ffff\:ffff\:\:fffe=LA1:RAC1
ffff\:0\:ffff\:ffff\:\:ffff=LA1:RAC2

# default for unknown nodes
default=NY1:RAC1


My Keyspace replication strategy is as follows:
Keyspace: SipTrace:
  Replication Strategy: org.apache.cassandra.locator.NetworkTopologyStrategy
    Options: [LA1:1,NY1:1]

So each data center should get 1 copy of the data, and this does
happen.  The problem is that the replicated copies get pinned to the
first host configured in the properties file, from what I can discern,
and DO NOT distribute between racks.  So I have 2 nodes that have a 4
to 1 ratio of data compared to the other 2 nodes.  This is a problem!

Can any one please tell me if I have misconfigured this?  Or how I can
get replica data to distribute evenly between racks within a
datacenter?  I was led to believe that cassandra will try to
distribute between racks for replica data automatically under this
setup.

Thank you for your help in advance!

-Eric

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