Apologies if this is obvious, but I'm not that experienced with Linux/Unix and a search ( which has resolved other stumbling blocks on my journey ) hasn't helped with this issue.
The machine has a 4GiB SSD for OMV and a 2Tb drive for data. This machine is intended for backup only and everything else seems to work fine including RSync from the main OMV NAS. I appreciate that the 4GiB SSD is right at the minimum h/w requirement.
Anyway, looking at Storage/Disks, the 4GiB SSD is reported as a 4GiB flash drive with 3.81GiB capacity. This is the same in Storage/S.M.A.R.T. That's as expected.
However, in Storage/File Systems the disk ( ext4 ) is reported as 2.12GiB and currently only has 7.73MiB available!
What happened to the other space? I seem to be missing around 1.5GiB.
OMV : 4.1.21-1