[ceph-users] OSD's still UP after power loss

Hello I have a weird problem on 3 node cluster. "Nautilus 14.2.9" When I try power failure OSD's are not marking as DOWN and MDS do not respond anymore. If I manually set osd down then MDS becomes active again. BTW: Only 2 node has OSD's. Third node is only for MON. I've set mon_osd_down_out_interval = 0.3 in ceph.conf at global section and restart all MON's but when I check it with "ceph daemon mon.ID config show" I see mon_osd_down_out_interval: "600". I didn't get it why its still "600" and honestly I don't know even it has any effect on my problem. Where should I check?