Hi all, stumbling over a new ceph cluster setup, I got a basic question regarding the behaviour of ceph. The cluster I found runs 4 hardware nodes as hyper convergent instances - 3 nodes running MON and several OSD instances while one node only runs several OSD. At the same time, all nodes serve as KVM hosts, running several VMs. Replication is set to three. 1.) Am I right that in this setup only one node may fail without leaving the cluster unresponsive? (i.e. rejecting further IO)? if two nodes fail, the cluster will stop serving IO (but probably won't lose data if at least one of the two failing nodes can recover) 2.) Am I further right, that this setup with four nodes might provide a little better IO to the VMs than if it would run on only three nodes (all of whom run OSD and OSD and KVM), but 3.) in a setup with 5 nodes, the IO performance delivered to the VMs would be even better and if all of the 5 nodes would run MON and OSDs and KVM, any two nodes might fail without leaving the cluster unresponsive? (sure one would have to move/restart the VMs on the failing nodes ... just from the underlying data integrity point of view) Sorry if it sounds dumb, seems sort of obvious to me, but I have to nail this cristal clear. Short, comprehensive answer would be most appreciated! Best regards!