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:  http://docs.datastax.com/en/cassandra/2.1/cassandra/operations/opsChangeKSStrategy.html  
that does not mention anything about repairing the cluster

For Cassandra 3 I found this other doc:  https://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsChangeKSStrategy.html  
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
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