One thing to keep in mind with clusters is quorum. You need “half the nodes +1” up and running for the cluster to operate normally. Having isolated servers circumvents this.

I ran into this when I built a test cluster with 5 nodes. Found out I needed at least 3 nodes powered on to do anything. I now have a 2 node cluster (with my laptop running a qdevice for quorum) and 2 isolated nodes. Translates into some decent power savings…