Are the drive SCSI? just sayin.
As @etorix has said, if you are not passing through the entire drive controller then you are doing it incorrectly and the possibility of data loss is real. I ran ESXi and used RDM for a few years, while I was very disciplined in how I operated the system, I eventually bought a cheap no frills controller (HBA) and passed through the controller and my data is much safer. It also makes setting up a TrueNAS VM significantly easier.
EDIT:
sudo smartctl -x /dev/sdb try to use sudo smartctl -d sat -x /dev/sdb, it may work (SCSI to ATA Translation), or it may not.