Yes, you can do that. That's when you put all the cluster peers in the
Allocations for a CID (or simply leave it empty). But every CID carries on which peers it should be pinned and that list can vary per CID (some can be pinned everywhere and others not).
I'm not sure we call "a cluster" the same thing. If you have a list of CIDs and you are pinning them to different peers you can:
- Say you have a single cluster with different allocations per CID
- Say you have a different pinset per cluster peer
- Say you have different clusters which share a single pinset.
It's all the same. All is a map between CIDs and the Peers they need to be pinned and if all those peers are connected and can access each others content and information, I would call that a single Cluster because a single IPFS Cluster does that.
A Cluster for me is something fully independent which consists in a set of peers which share a pinset (even if they don't have to pin everything in it). You could also have several "clusters" where everything is pinned everywhere (one per dataset) and get the same result.