I have a use case where I want to only use a small portion of the disk for the OSD and the documentation states that I can use data_allocation_fraction [1] But cephadm can not use this and throws this error: /usr/bin/podman: stderr ceph-volume lvm batch: error: unrecognized arguments: --data-allocate-fraction 0.1 So, what I actually want to achieve: Split up a single SSD into: 3-5x block.db for spinning disks (5x 320GB or 3x 500GB regarding if I have 8TB HDDs or 16TB HDDs) 1x SSD OSD (100G) for RGW index / meta pools 1x SSD OSD (100G) for RGW gc pool because of this bug [2] My service definition looks like this: service_type: osd service_id: hdd-8tb placement: host_pattern: '*' crush_device_class: hdd spec: data_devices: rotational: 1 size: ':9T' db_devices: rotational: 0 limit: 5 size: '1T:2T' encrypted: true block_db_size: 320000000000 --- service_type: osd service_id: hdd-16tb placement: host_pattern: '*' crush_device_class: hdd spec: data_devices: rotational: 1 size: '14T:' db_devices: rotational: 0 limit: 1 size: '1T:2T' encrypted: true block_db_size: 500000000000 --- service_type: osd service_id: gc placement: host_pattern: '*' crush_device_class: gc spec: data_devices: rotational: 0 size: '1T:2T' encrypted: true data_allocate_fraction: 0.05 --- service_type: osd service_id: ssd placement: host_pattern: '*' crush_device_class: ssd spec: data_devices: rotational: 0 size: '1T:2T' encrypted: true data_allocate_fraction: 0.05 [1] https://docs.ceph.com/en/pacific/cephadm/services/osd/#ceph.deployment.drive... [2] https://tracker.ceph.com/issues/53585 -- Die Selbsthilfegruppe "UTF-8-Probleme" trifft sich diesmal abweichend im groüen Saal.