Hi all, Have a question regarding CephFS and write performance. Possibly I am overlooking a setting. We recently started using Ceph, where we want to use CephFS as a shared storage system for a Sync-and-Share solution. Now we are still in a testing phase, where we are also mainly looking at the performance of the system, where we are seeing some strange issues. We are using Ceph Quincy release 17.2.6, with a replica 3 data policy across 21 hosts spread across 3 locations. When I write multiple files of 1G, the writing performance drops from 400MiB/s to 18 MiB/s with also multiple retries. However, when I empty the page caches every minute on the client, the performance remains good. But that's not really a solution of course. Have already played a lot with the sysctl settings, like vm.dirty etc, but it makes no difference at all. When I enable the fuse_disable_pagecache, the write performance does stay reasonable at 70MiB/s, but the read performance completely collapses from 600 MiB/s to 40 MiB/s There is no difference in behavior between the kernel or fuse client. Have already played around with client_oc_max_dirty, client_oc_max_objects, client_oc_size , etc. But haven't found the right setting. Anyone familiar with this who can give me some hints? Thanks for your help! :-) Kind regards, Tom