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If the number of vNodes in the existing Cassandra 2.2.x cluster is changed - will it cause all the data in that cluster to be lost or not?
Is it possible to change # of vNodes and keep all the data stored in the Cassandra cluster?

Aaron
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user3791111
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1 Answers1

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The value in the config (cassandra.yaml) is only read on startup. Changing the value here will basically have no effect. You won't lose data.

There used to be a feature called shuffle - but it turned out you really don't want to change the token layout in this way, the streaming associated with shuffle will pretty much kill your cluster.

If you need to do this - the best method is to create a new DC with the desired token ranges and then rebuild them as per the instructions here:

https://docs.datastax.com/en/cassandra/2.1/cassandra/operations/ops_add_dc_to_cluster_t.html

You can then point your app at the new DC and throw away the old.

Nom de plume
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