One would think that hdparm -S 254 /dev/device or something close would take care of it like it would on any laptop hard drive that supports head parking, but no.
Western Digital: what's up with this? Why does your firmware have to be so different and auto head parking after 6 (or is it 8?) seconds not be turned off?

Now, there is an unsupported and technically "void your warranty" solution (which is ironic considering that not doing anything will kill the drives and cause warranty returns within about 1 to 2 years for me): wdidle3 from their site and also wdspinup .

Now, the other problem is that those are green drives and they were taking more power than my other drives because I could not spin them down (I don't use my drives more than a few times a day in a machine where they are on all the time).

The sad thing is that my solution to this was to write a quick program that checks whether the drive has been used recently (using iostat) and manually spin it down with hdparm -y if it has not.

You can get swdisksusp.