I wanted to mount an existing filesystem (exfat on SAMSUNG 2Tb SSD) via OMV.
I could see the disk ok, but when I created a shared folder I was told that there was a permissions problem which stopped it from happening. I tried again, and the shared folder appeared in the drop down list.
Then I tried to share via NFS. No go. #The command failed to execute' (with lots of detail that didn't help solve the problem.
Work Around
No problems sharing an ext4 HDD, so I reformatted the SSD (I used ext4). Everything worked beautifully after that.