I use Raw Device Mapping on a VMware vSphere 5.0 server to passthrough several disks directly to the VM. I use the Physical Passthrough mode so that the guest ends up seeing the disk almost exactly as it should. The output from hdparm and smartctl seem to be no different than what I would expect if these disks were attached to a native linux system.

The problem comes in that smartctl is able to report the temperature of the disks, but hddtemp isn't able to detect the temperature sensor. Since hddtemp claims to make use of SMART data, it seems that it's not looking at the same source as smartctl.

snogard ~ # hddtemp /dev/sdb
/dev/sdb: ATA ST31500341AS:  drive supported, but it doesn't have a temperature sensor.
snogard ~ # smartctl -x /dev/sdb | grep -i "Current Temperature"
Current Temperature:                    33 Celsius
snogard ~ # hddtemp -v
hddtemp version 0.3-beta15

I know this is kind of a weird setup and probably unsupported on all fronts, but it would be rather nice to get hddtemp working on this system.