Hi, after adding an OSD to Ceph it is adviseable to create a relevant entry in Crush map using a weight size depending on disk size. Example: ceph osd crush set osd.<id> <weight> root=default host=<hostname> Question: How is the weight defined depending on disk size? Which algorithm can be used to calculate the weight? From my first Ceph installation (luminous) the Crush map entry for - HDD device with 1.80TB size (output of lsscsi -s): weight was 1.627229 - NVMI device with 3.20TB size (output of lsscsi -s): weight was 2.910889 THX