Dear cephers, today it seems I observed an impossible event for the first time: an OSD host crashed, but the ceph health monitoring did not recognise the crash. Not a single OSD was marked down and IO simply stopped, waiting for the crashed OSDs to respond. All that was reported was slow ops, slow meta data IO, MDS behind on trimming, but no OSD fail. I have rebooted these machines a lot of times and have never seen the health check fail to recognise that instantly. The only difference I see is that these were clean shut-downs, not crashes (I believe the OSDs mark themselves as down). For debugging this problem, can anyone provide me with a pointer when this could be the result of a misconfiguration? Thanks and best regards, ================= Frank Schilder AIT Risø Campus Bygning 109, rum S14