Hi, We experienced a strange issue with a CephFS snapshot becoming partially unreadable. The snapshot was created about 2 months ago and we started a read operation from it. For a while everything was working fine with all directories accessible, however after some point clients (FUSE, v15.2.9) started complaining about I/O error on directories that were working fine previously. When listing the top level contents of the snapshot, the directories that show I/O error (e.g. home) are reporting missing metadata when listing via 'ls': d????????? ? ? ? ? ? home Creating new snapshots is working properly and otherwise the whole cluster (Ceph v15.2.9) is reporting a healthy status. Has anyone experienced an issue like this before? We tried to restart the MDS servers, however this didn't solve the issue. As additional context, during the read time from the snapshot other snaptrim operations (for other subvolumes) were ongoing, but not for the one affected by the data error. Any insight into what might cause this and how to avoid / recover from such a situation would be much appreciated. Thank you and kind regards, Andras