If the node's only been down for less than gc_grace_seconds and the data in the drives are intact, you should be fine just booting the server and it will join the cluster. You will need to run a repair so it picks up the missed mutations.
@Bowen FWIW no need to do a "replace" -- the node will just take over the new IP. You'll just see a warning in the system.log that looks like: Not updating host ID <host_id> for <ip> because it's mine See https://github.com/apache/cassandra/blob/cassandra-4.0-beta3/src/java/org/apache/cassandra/service/StorageService.java#L2620. Cheers!
