Ceph

If we have to do heartbeating over the exact same connection we send our other traffic on, is there any advantage to having the separate heartbeat messenger at all? Since it has its own dispatch loop it can obviously be lower-latency, but it's not clear to me that we actually gain that much advantage from multiple low-latency connections if we can't count on it to mean we're functioning.
(ie if the cluster network fails we might take 10 seconds to detect it instead of 2, but does that kind of detection speed actually help us in that failure scenario?)