I have been successfully using NFS shares from my OMV server for my media centers and my laptop for about six months. Once I cleared a few bugs in my setup they have been good and stable. However suddenly out of the blue they stopped working about a week ago. This impacts all my clients which sort of points to the server been the cause of the problem. The behaviour is the Share folders are still broadcast and discoverable and I can add them to my clients as before. However once connected the client folders are simply empty and will not populate.
I have made no changes to my NFS settings in OMV, but I regularly accept software updates on my server. My server also runs Pi-Hole, Urbackup, TVheadend server and Squid. Some upgrade must have broken a NFS subsystem on my server box.
The NFS server within the GUI of OMV all looks OK and unchanged with no errors and as I said I have not touched NFS for months. My fix is to migrate back to SMB which works fine for my use case, but I would really like to resolve this issue with NFS.