I have 2 clusters. Cluster 1 started at Hammer and has upgraded through the versions all the way to Nautilus 14.2.10 (Luminous to Nautilus in July 2020) . Cluster 2 started as Luminous and is now Nautilus 14.2.2 (Upgraded in September 2019) The clusters are basically identical 5 OSD Nodes with 6 osd's per node. They are both using disk drives. No SSD's. Prior to upgrading Cluster 1 running "ceph tell osd.0 bench -f plain" produced similar results across both clusters. ceph tell osd.0 bench -f plain bench: wrote 1 GiB in blocks of 4 MiB in 0.954819 sec at 1.0 GiB/sec 268 IOPS Now cluster 1 results are terrible, about 25% from before the upgrade. ceph tell osd.0 bench -f plain bench: wrote 1 GiB in blocks of 4 MiB in 4.03434 sec at 254 MiB/sec 63 IOPS Ceph -s shows HEALTH_OK. Dashboard looks good. 2 pools MON Dump min_mon_release 14 (nautilus) OSD Dump require_min_compat_client luminous min_compat_client jewel require_osd_release nautilus Not sure what is causing the slow performance. Ideas?