Steps and recommendations for enabling virtual nodes (vnodes) on an existing
production cluster.
You cannot directly convert a single-token nodes to a vnode. However, you can
configure another datacenter configured with vnodes already enabled and let
Cassandra automatic mechanisms distribute the existing data into the new nodes. This
method has the least impact on performance.
Procedure
-
Add a new datacenter
to the cluster.
-
Once the new datacenter with vnodes enabled is up, switch your clients to use
the new datacenter.
-
Run a full repair with nodetool
repair.
This step ensures that after you move the client to the new datacenter that
any previous writes are added to the new datacenter and that nothing else,
such as hints, is dropped when you remove the old datacenter.
-
Update your schema to no longer reference the old datacenter.
-
Remove the old datacenter from the cluster.