I have a new OMV installation, and notice the SMART info is not being read for my external hard drives.
On other linux installations I use commands like this to get SMART working on those same drives, and the addition of the option -d sat is key,
smartctl --health -d sat /dev/sdb
That particular command doesn't work on OMV and just gives an error,
Read Device Identity failed: scsi error unsupported field in scsi command.
The drives are seagate 2.5 inch drives.
For instance this is what I have used in the past. Putting a file similar to this in /etc/cron.daily/ gives a daily SMART status email,
#!/bin/sh
(
echo "==SDA=="
smartctl --health /dev/sda
echo "==SDB=="
smartctl --health -d sat /dev/sdb
echo "==SDC=="
smartctl --health /dev/sdc
echo "==SDD=="
smartctl --health -d sat /dev/sdd
echo "==SDE=="
smartctl --health /dev/sde
echo "==SDF=="
smartctl --health /dev/sdf
) | /bin/mail -s 'NAS Status' youremailaddres@something.com