Dear Ceph’ers I am about to upgrade MDS nodes for Cephfs in the Ceph cluster (erasure code 8+3 ) I am administrating. Since they will get plenty of memory and CPU cores, I was wondering if it would be a good idea to move metadata OSDs (NVMe's currently on OSD nodes together with cephfs_data ODS (HDD)) to the MDS nodes? Configured as: 4 x MDS with each a metadata OSD and configured with 4 x replication so each metadata OSD would have a complete copy of metadata. I know MDS, stores al lot of metadata in RAM, but if metadata OSDs were on MDS nodes, would that not bring down latency? Anyway, I am just asking for your opinion on this? Pros and cons or even better somebody who actually have tried this? Best regards, Jesper -------------------------- Jesper Lykkegaard Karlsen Scientific Computing Centre for Structural Biology Department of Molecular Biology and Genetics Aarhus University Gustav Wieds Vej 10 8000 Aarhus C E-mail: jelka@mbg.au.dk<mailto:jelka@mbg.au.dk> Tlf: +45 50906203