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From Dominik Petrovic <>
Subject Re[2]: Modify keyspace replication strategy and rebalance the nodes
Date Thu, 14 Sep 2017 15:47:44 GMT
Thank you for the replies!

@jeff my current cluster details are:
1 datacenter
40 nodes, with vnodes=256
What is your advice? is it a production cluster, so I need to be very careful about it.

>Thu, 14 Sep 2017 -2:47:52 -0700 from Jeff Jirsa <>:
>The token distribution isn't going to change - the way Cassandra maps replicas will change. 
>How many data centers/regions will you have when you're done? What's your RF now? You
definitely need to run repair before you ALTER, but you've got a bit of a race here between
the repairs and the ALTER, which you MAY be able to work around if we know more about your
>How many nodes
>How many regions
>How many replicas per region when you're done?
>Jeff Jirsa
>On Sep 13, 2017, at 2:04 PM, Dominik Petrovic < >
>>Dear community,
>>I'd like to receive additional info on how to modify a keyspace replication strategy.
>>My Cassandra cluster is on AWS, Cassandra 2.1.15 using vnodes, the cluster's snitch
is configured to Ec2Snitch, but the keyspace the developers created has replication class
SimpleStrategy = 3.
>>During an outage last week we realized the discrepancy between the configuration and
we would now fix the issue using NetworkTopologyStrategy. 
>>What are the suggested steps to perform?
>>For Cassandra 2.1 I found only this doc:
>>that does not mention anything about repairing the cluster
>>For Cassandra 3 I found this other doc:
>>That involves also the cluster repair operation.
>>On a test cluster I tried the steps for Cassandra 2.1 but the token distribution in
the ring didn't change so I'm assuming that wasn't the right think to do.
>>I also perform a nodetool repair -pr but nothing changed as well.
>>Some advice?
>>Dominik Petrovic

Dominik Petrovic
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