There’s a bunch of people in this thread, who seem a little bit too goofy to figure out that you were just asking how did defend against RansomWare basically find something that uses snapshots

3-2-1-1-0 backup rule and you don't have to worry about randsomware. Can't encrypt what is offline.

we're talking about a diy nas or a sinology one?

Maybe you could try encrypting a volume that you will only use for backups and leave it unmounted when you aren’t using it?

Best way to configure a NAS is with backups.

Assuming you actually want a NAS and not cold storage, I’d recommend at least some kind of raid to account for disk failure.

As for ransomware protection, one decent solution is snapshots and limiting every client to only be allowed access to their own backup directory, or a limited set of directories in general on the NAS, as well as no execution permissions in those directories.

If you’re concerned about the NAS being directly infected by a malicious user with direct access and execute permissions, the only real solution is offsite or cold storage backups.