Hi Guys, I have 7 OSD nodes with 10X15T NVME disk on each OSD node. To start with , I want to use only 8X15T disk on each osd node and keep 2X15 disk spare in case of any disk failure and recovery event. I am going to use the 4X2 EC CephFS data pool to store data. So, with the above set-up, what will be the optimal number of placement groups per OSD. As per the PG calculator :- ( 8X7X100 ) / 6 = 933.33 nearest power of 2 is 1024. With 1024 placement groups distributed across 56 OSDs, that evaluates to approximately 18 placement groups per OSD. I don't think its optimal as Ceph doc recommends 50-100 PG per OSD. So, am I doing something wrong? or missing something white calculating the number of PG per OSD. Also, will it be best practice to keep 2X15T disk spare on each OSD or should I use all of them. Also, I am going to deploy 7 OSD nodes across 4 Racks and will be using the failure domain as "rack" to have Ceph handle the entire rack failure. I hope this will provide more protection. Please advise. Thanks, Gagan Thanks, Gagan.