Dear Ceph users, I'm trying to export a CephFS with the root_squash option. This is the client configuration: client.wizardfs_rootsquash key: XXXXXXXXXXXX caps: [mds] allow rw fsname=wizardfs root_squash caps: [mon] allow r fsname=wizardfs caps: [osd] allow rw tag cephfs data=wizardfs I can mount it flawlessly on several machines using the kernel driver, but when a machine writes on it then the content seems fine from the writing machine but it's not actually written on disk since other machines just see an empty file: [12:43 mori@stryke ~]$ echo test > /wizard/ceph/software/el9/test [12:43 mori@stryke ~]$ ll /wizard/ceph/software/el9/test -rw-r--r-- 1 mori wizard 5 mag 15 12:43 /wizard/ceph/software/el9/test [12:43 mori@stryke ~]$ cat /wizard/ceph/software/el9/test test [12:43 mori@stryke ~]$ [mori@fili ~]$ ll /wizard/ceph/software/el9/test -rw-r--r--. 1 mori 1014 0 May 15 06:43 /wizard/ceph/software/el9/test [mori@fili ~]$ cat /wizard/ceph/software/el9/test [mori@fili ~]$ Unmounting and then remounting on "stryke" the file is seen as empty, so I guess that the content shown just after the write is only a cache effect and nothing is effectively written on disk. I checked the posix permissions on the folder and I have rw rights from both the machines. All of the above using Ceph 18.2.2 on the cluster (deployed with cephadm) and both the machines. Machine "fili" has kernel 5.14.0 while "stryke" has 6.8.9. The same issue happens consistently also in the reverse direction (writing from "fili" and reading from "stryke"), and also with other machines. Removing the squash_root option the problem vanishes. I don't know what might