Does anyone know if Lemmy has support for a “replicated instance”?
What I’m imagining is a backup of all Communities and Posts at least, in such a way that does not cause a nightmare for the Federated feed, but could be swapped in if something were to happen to the original?
Yes, postgres supports replication if you own the instance you’re trying to replicate.
If not, you could write up a script pretty easily using the api to copy the data you want.