I got that sorted out. I had to re-create the MON data directory on this node, and this seems to have been enough, even if not trivial. I'm not sure if it helped that I destroyed cephfs (not yet used) and the MDS daemons... I was lulcky I could do that. /lesson learned : upgrade MONs first/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com