I just upgraded from Luminous to Nautilus. the cluster was originally hammer or kraken (can't recall), then jewel, on to luminous, and now Nautilus. The message i get from ceph -s is: "health: HEALTH_WARN crush map has legacy tunables (require firefly, min is hammer)" Not sure how to get rid of it. I tried "ceph osd set-require-min-compat-client firefly" per instructions but still have error. When I query osd: ceph osd dump | grep min_compat_client require_min_compat_client firefly min_compat_client firefly Instructions say I can ignore the error, but that seems like a bad idea. Windows VM's are running on qemu/kvm via rbd connection. Ceph and KVM are running CentOS7. Just upgraded all clients to "centos-release-7-8.2003.0.el7.centos.x86_64" I have rebooted all nodes since CentOS upgrade and again after Nautilus upgrade. tried setting "ceph osd set-require-min-compat-client jewel" but then heath_warn was still present and: ceph osd dump | grep min_compat_client require_min_compat_client jewel min_compat_client firefly Any help is appreciated.