Apple software RAID 0 not spinning down while not in use

Question

I have a G-Tech G-RAID w/ Thunderbolt, 8TB external enclosure.  It has two 4TB fujitsu drives in it, set up as RAID 0 with Apple's Disk Utility v13 (426) that ships with 10.8 Mountain Lion.  This is attached to a very cleanly installed Mid 2011 Mac Mini, which is acting as a media server.  There is basically no 3rd party software on it, because it's acting as a NFS filer server for streaming digital players around the house.
However, I have the G-RAID set to spin down when possible in energy saver, and it's not.  It never spins down.  I have 4 external drives on this media server, ranging from USB to FW800 to the Thunderbolt drive, all from different manufacturers, and different sizes and models.  All the other drives spin down after 10 minutes.
Not only is the checkbox "Put hard disks to sleep when possible" checked in Energy Saver, but a
pmset -g
reveals that the "disksleep" is set to 10 (min).
In frustration, I have tried a lot of things including (but not limited to) removing all other hard drives and hardware, starting up with shift held (safe boot) and removing any software at all that I thought would be keeping the drive "alive."
Finally I decided to start monitoring the drive with fs_usage, to see if I could suss out what is keeping this one drive alive.
"fs_usage | grep DISKNAME" reveals that SystemUIServer is accessing the drive every minute, about seven times in a clump.  Considering that SystemUIServer is the peice of software that controls the little menu add-ons to the right of the menubar, I have spend a great deal of time trying to figure out what would use SystemUIServer that is accessing this drive.
Now it's true that this drive is set up as a time machine drive, but I have disabled time machine, and spotlight, and still I get the same SystemUIServer accesses every minute.  Here is a fs_usage dump:
orion:~ seanb$ sudo fs_usage | grep Betelgeuse
Password:
15:53:16  getattrlist       /Volumes/Betelgeuse     0.000029   SystemUIServ
15:53:16  getattrlist       /Volumes/Betelgeuse     0.000011   SystemUIServ
15:53:16  getattrlist       /Volumes/Betelgeuse     0.000017   SystemUIServ
15:53:16  getattrlist       /Volumes/Betelgeuse     0.000010   SystemUIServ
15:53:16  getattrlist       /Volumes/Betelgeuse     0.000008   SystemUIServ
15:53:16  getattrlist       /Volumes/Betelgeuse     0.000010   SystemUIServ
15:53:16  statfs64          /Volumes/Betelgeuse     0.000017   SystemUIServ
15:54:16  getattrlist       /Volumes/Betelgeuse     0.000025   SystemUIServ
15:54:16  getattrlist       /Volumes/Betelgeuse     0.000007   SystemUIServ
15:54:16  getattrlist       /Volumes/Betelgeuse     0.000011   SystemUIServ
15:54:16  getattrlist       /Volumes/Betelgeuse     0.000011   SystemUIServ
15:54:16  getattrlist       /Volumes/Betelgeuse     0.000009   SystemUIServ
15:54:16  getattrlist       /Volumes/Betelgeuse     0.000010   SystemUIServ
15:54:17  statfs64          /Volumes/Betelgeuse     0.000014   SystemUIServ
15:55:17  getattrlist       /Volumes/Betelgeuse     0.000062   SystemUIServ
15:55:17  getattrlist       /Volumes/Betelgeuse     0.000013   SystemUIServ
15:55:17  getattrlist       /Volumes/Betelgeuse     0.000024   SystemUIServ
15:55:17  getattrlist       /Volumes/Betelgeuse     0.000010   SystemUIServ
15:55:17  getattrlist       /Volumes/Betelgeuse     0.000009   SystemUIServ
15:55:17  getattrlist       /Volumes/Betelgeuse     0.000010   SystemUIServ
15:55:17  statfs64          /Volumes/Betelgeuse     0.000014   SystemUIServ
As you can see, it's the same seven drive accesses every minute.  This is NOT occuring with any of my other drives.  Now, here comes my wild conjecture.  Is this something the system does because they are RAID slices?  Do OS X software RAID slices check themselves every minute? This seems to be preventing them from sleeping.
Any help would be appreciated, I'm going nuts here.
Sean

Answer 1

The second column in your fs_usage report says that iStat Menus is what is accessing your disk (Istat64).  Disable iStat Menus and I bet your issue will go away.  I know there is a module in iStat Menus to monitor drive space, but if I recall correctly, even if that module is disabled, iStat has a habit of checking drives anyhow.  I remember hearing people getting rid of istat menus in order to allow their HDs to sleep propely.
In fact, and easy way to test this would be to reboot your Mac with the shift key held down until you see your desktop load up.  This will prevent 3rd party add-ons from loading like iStat Menus. Let me know if that works.
Unfortunatrly this is not the problem I am having, as I've booted with shift, and I still see the  "getattrlist" accesses in my fs_usage report.
EDIT: stupid font made your report look like iStat when it was Lstat.  So what I said about iStat Menus is probably incorrect.  But using the shift key to boot could still lead you to the correct anwer.  I'm doing testing on my end as well. Let you know if I see anything that pertains to your issue.  (I got an Lstat entry in my fs_usage when I open the drive during testing, but I have not beeing getting them an regular intervals like you do.  I would still guess that you have 3rd party software that is checking on drives periodically, and that holding shift might suss that out.)
Message was edited by: Cheule