We have recently started to look into that and our approach at this stage is working only for setups, where we use in the external USB enclosure Sata HDDs. For IDE HDDs it seems not to work.
yum install sg3_utils
This package includes a lot of HDD related tools/utilities. Have a look, there might be something better then what we use at the moment. For example:
sg_start 0 /dev/sdc1