Am 03.05.21 um 11:22 schrieb Ilya Dryomov: max_osd 12 I never had more then 10 osds on the two osd nodes of this cluster. I was running a 3 osd-node cluster earlier with more than 10 osds, but the current cluster has been setup from scratch and I definitely don't remember having ever more than 10 osds! Very strange! I had to replace 2 disks because of DOA-Problems, but for that I removed 2 osds and created new ones. I used ceph-deploy do create new osds. To delete osd.8 I used: # take it out ceph osd out 8 # wait for rebalancing to finish systemctl stop ceph-osd@8 # wait for a healthy cluster ceph osd purge 8 --yes-i-really-mean-it # edit ceph.conf and remove osd.8 ceph-deploy --overwrie-conf admin s0 s1 # Add the new disk and: ceph-deploy osd create --data /dev/sdc s0 ... it get's created with the next free osd num (8) because purge releases 8 for reuse