after initially experimenting with OMV some time back on my raspberry pi (single client backup+airplay) I got ahold of a HP HomeServer which I used a while with macOS installed (local home photo-sharing) and later after I migrated my photo-library to iCloud with XPEnology.
While the overall user experience is great the network read performance is subbar with any OS which I suspect the hacky XPEnology network drivers to blame for.
Preparing an external OMV flash install (4 internal drives dedicated to RAID5) went fine and the RAID can be seen and mounted after some fiddling around. What does not work however are the BTRFS sub-volumes. Neither do they show up as sub-volumes using the Btrfs utils (though I might have gone wrong? Btrfs show /sub/volume/path ) nor there is any error when checking the filesystem. However they are listed as not accessible folders in their respected top level directors with wired permissions.
How may I mount them/add them to fstab to auto mount them?
PS.: Booting back to XPEnology again I can access the volumes just like regular folders.