Steps and recommendations for enabling virtual nodes (vnodes) on an existing
production cluster.
For production clusters, enabling virtual nodes (vnodes) has less impact on
performance if you bring up a another data center configured with vnodes already
enabled and let Cassandra automatic mechanisms distribute the existing data into the
new nodes.
Procedure
-
Add a new data center
to the cluster.
-
Once the new data center with vnodes enabled is up, switch your clients to use
the new data center.
-
Run a full repair with nodetool
repair.
This step ensures that after you move the client to the new data center that
any previous writes are added to the new data center and that nothing else,
such as hints, is dropped when you remove the old data center.
-
Update your schema to no longer reference the old data center.
-
Remove the old data center from the cluster.