[gentoo-user] Problem with power management of SATA hard drives

[Ralf <ralf+gentoo@ramses-pyramidenbau.de>]

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Hi there,

I'm using Gentoo ~amd64 on my NAS.

This is my setup:
Mainboard - Asus E35M1
CPU - AMD E350
HDD - 1x 500GiB WD Caviar Green WD5000AADS (root)
HDD - 4x 3TiB WD Caviar Green WD30EZRX (Raid10)

As these hard drives are desktop hard drives and not designed for 24/7
purposes, I want to spin them down when they are not in use.
(And in fact, they will probably be idling most of the time, so let's
save energy)

I'm able to force spin down those drive by using hdparm -y. hdparm -C
then tells me, that they switched from active/idle to standby.
Setting standby-time using hdparm -S also seems to work fine:

    hdparm -S 10 /dev/sdb

    /dev/sdb:
     setting standby to 10 (50 seconds)

But this does not standby my drive after 50 seconds. So I tried to set
the Power Management Level:

    hdparm -B 5 /dev/sdb

    /dev/sdb:
     setting Advanced Power Management level to 0x05 (5)
     HDIO_DRIVE_CMD failed: Input/output error
     APM_level      = not supported


Obviously, my system does not support APM what I can hardly believe...
So I tried to enable APM but my kernel configuration doesn't allow me to
enable APM support as long as I use a 64 bit kernel - APM option is only
available for 32 bit kernels.

What am I doing wrong? My hardware is *relatively* new and I don't
believe that it doesn't support those power management features.

But besides that, does anyone have further tips or tricks to protect
hard drives? E.g. try to minimize Load Cycle Count, ...

Output of hdparm -I: http://pastebin.com/RyAU6u8T

Cheers,
  Ralf

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