O my goodness o my dayum!
I was thinking about this since years! Never came that far that the hd actually went to sleep. My idea was to have the root filesystem on a usb-stick and just /boot & /data on the hd.
I even successfully installed my system once like these but never had luck to send the hd to sleep.. Then I gave it up... now i read this and think - WOW!
I use my NAS as a server so I have a couple of things running...
I wan't to do a card&caldav server as well. But this would all work on the system partition (root) and these could be on the stick...
Could you give me a small briefing how you managed this wonderful setup? I'm not a pro and have some troubles with your short explainings
I mounted all ext filesystems with noatime and issued
echo -n 0 > /proc/sys/vm/swappiness
hddparm -S 6 /dev/sda