Dears, maybe someon can explain/answer my question. We are working on setting up a new ceph cluster (underneath a proxmox cluster), the setup is as follows 3 datacenters 3 hosts per datacenter (all in one rack) 8 physical disks per host This is the profile configutation ceph osd erasure-code-profile set ec_profile plugin=isa technique=reed_sol_van k=4 m=2 crush-root=default crush-failure-domain=datacenter crush-device-class=nvme crush-osds-per-failure-domain=2 crush-num-failure-domains=3 We have a hierarchy - created with a custom_location_hook that contains * datacenter 01 * rack 01 * host 01 * host 02 * host 03 * datacenter 02 * rack 01 * host 01 * host 02 * host 03 * datacenter 03 * rack 01 * host 01 * host 02 * host 03 So this means (my understanding) that we are placing 2 shards of data in each datacenter. We want to make sure that we only have max one share of data per host, and in future if possible also distributed across racks once we should ahve more per DC. Is the bucket hierarchy automatically taken into account when choosing the OSD ? Or if not, where do i start, with CRUSH rules ? (I am hesitant to manually modify CRUSH rules. Thanks in advance Soeren