+1 to Justin's answer!
As an additional step it's always good to run a full repair before deleting
data on existing nodes, as there is a possibility of ioexceptions during
rebuild. (Things like https://issues.apache.org/jira/browse/CASSANDRA-12830)
Also if you are on 3.8+ , you may go for CDC app
Yes - this is the recommended way to migrate to another DC.
Before you start the migration you'll need to ensure
1. that the replication strategy of all your keyspaces is
NetworkTopologyStrategy (if not, change it to this using ALTER KEYSPACE),
and
2. that each of your clients is using the DcAware
Have a scenario where it's necessary to migrate a cluster to a different
set of hardware with minimal downtime. Setup is:
Current cluster: 4 nodes, RF 3
New cluster: 6 nodes, RF 3
My initial inclination is to follow this writeup on setting up the 6 new
nodes as a new DC:
https://docs.datastax.com