So, just need to wait. Is that correct? Which version of operator support this?
I believe all versions of the operator should support this.
On a separate question, what if someone removed the pods manually BEFORE the data movement finished and resulting in UNHEALTHY: No replicas remain of some data. Is running restore the only way to recover?
Since version 1.2.0 those Pods are recreated until they are fully excluded (data movement finished): Release v1.2.0 · FoundationDB/fdb-kubernetes-operator · GitHub
What if say, I changed the size, and the new storage pods got created. And before it can finish migration, I deleted all the old storage pods and now the DB is telling me it is in a “Unhealthy state, some data don’t have any replica”. Is there a way to clean the db of all the data and put it back into a healthy state so that I can do a restore?
Like above the operator (1.2.0+) should recreate those Pods again and the cluster should be able to finish the data movement. You you to remove the whole key space, see this post for the command: Can't clear database (delete all data)