I've got a 2009 iMac (Intel Core 2 Duo) and I've noticed that the disks never sleep. I ran a power monitor and the iMac is using a third of our electricity every day!
I've checked via pmset that hibernatemode is set to 1 and when I purposefully click Apple > Sleep the iMac sleeps by saving state to RAM. However, if I just leave the device the screen sleeps but the disk never does.
I've unplugged all USB devices and made sure that bluetooth is not allowed to wake the device and that wake-on-lan is off
maxi:~ pauldambra$ pmset -g Active Profiles: AC Power -1* Currently in use: hibernatemode 1 halfdim 1 womp 0 sleep 2 powerbutton 1 disksleep 2 hibernatefile /var/vm/sleepimage ttyskeepawake 1 autorestart 0 displaysleep 1
I'm pretty new to Macs and Unix so I'm not really sure how I go about checking what is keeping the disks awake (or indeed if I've understood how disksleep works on a mac)
Many thanks in advance