Hallo all! I am configuring a new storage class on my Kubernetes cluster, pointing to a pool on a Ceph cluster which was recently upgraded to Nautilus (was Luminous). The old storage class points to a Luminous pool in a separate cluster and works fine. On the new one, I think I did the configuration properly, yet when creating a volume I get this: 2020-10-07 10:00:53.849128 7f2f8c6f9700 0 -- 10.2.3.13:0/3520982056 >> 10.2.3.23:6789/0 pipe(0x7f2f780008c0 sd=3 :60192 s=1 pgs=0 cs=0 l=1 c=0x7f2f780068e0).connect protocol feature mismatch, my 27ffffffefdfbfff < peer 27fddff8efacbfff missing 200000 Looking at https://ceph.io/geen-categorie/feature-set-mismatch-error-on-ceph-kernel-cl… looks like the 200000 corresponds to CEPH_FEATURE_MON_GV, which by the way is listed here https://github.com/ceph/ceph/pull/8214 as a feature which could/should be removed. Things being as I described, I guess it would be safe to change the value of the tunable, correct? Unfortunately, I was unable to find any way to achieve this... the trivial "ceph osd crush set-tunable mon_gv 0" does not work. Any idea, please, how to fix my error? Upgrading Ceph packages on Kubernetes workers (now at Luminous) would help, may be? Thanks! Fulvio -- Fulvio Galeazzi GARR-CSD Department skype: fgaleazzi70 tel.: +39-334-6533-250