My drives, all 3, go to sleep when I sleep the Mini 12. Drive lights are off and on powered hub. I use mine as a media server, if usb powered turned off then my wireless USB RF keyboard would be useless to power on PC from da couch! My BT mouse is dead until PC turned back on.
I can only suggest using using a 4 port or more USB hub with the on/off buttons on a desktop environment?