hdparm not working properly with esxi

hi,

I am using omv within my esxi server. I want to use hdparm to monitor whether the the hdds are spinning or not but i am getting error and it always indicates that the hdds are in standby mode.
This is the command i am using

hdparm -C /dev/sda

and the output im getting

SG_IO: bad/missing sense data, sb[]:   70 00 00 00 00 00 00 18 00 00 00 00 00 00 00 00 00 00 09 0c 00 00 00 ff 00 00 00 00 00 00 40 50
 drive state is: standby

The error is the same with each hdds
Anyone having the same problem with esxi? are there alternative methods to get hdd state information?
Below are my relevant configurations:
- esxi 5.0.0
- scsi controller lsi logic parallel (i am getting the same issue with lsi logic sas and paravirtual)
- hdd drives all mapped raw lun

I am using the 5.0 because it works with the nic that i am using while the 5.1 does not. If 5.1 solves this issue it is worth a try and hopefully they have already fix the problem with my nic but I am using the server also as router so long downtime is not preferable, i hope someone using omv within esxi 5.1 can post output of hdparm.