External usb hdd WD Elements - avoid spindown -- #2

A little update regarding the USB HDD spin-down-problem (discussed here: External usb hdd WD Elements - avoid spindown).
I found a better workaround somewhere (sorry to the original author - i forgot where...).

By default, the APM_level is set to 96(d) (60h) after every reconnect.
When setting this value to 128(d) (80h), the drive spins down after .. approx. 30-45 minutes (i haven't tested this exactly, but it definitely doesn't spin after.. lets say 1h).

The APM_level can be set with hdparm:

# hdparm -B /dev/disk/by-label/WD_500G_NTFS
/dev/disk/by-label/WD_500G_NTFS:
APM_level = 96

# hdparm -B 128 /dev/disk/by-label/WD_500G_NTFS
/dev/disk/by-label/WD_500G_NTFS:
setting Advanced Power Management level to 0x80 (128)
APM_level = 128

Note: The hard disk doesn't remember this setting. Like written before - after every reconnect it has its default setting of 96d.


Update1 / additional information:
The hdparm method works for me on the following Kernel:

$ uname -s -r -v -o
Linux 3.0.0-1-686-pae #1 SMP Sat Aug 27 16:41:03 UTC 2011 GNU/Linux

but on

uname -s -r -v -o
Linux 3.1.0-1-686-pae #1 SMP Mon Nov 14 08:24:20 UTC 2011 GNU/Linux

i get the following error when running hdparm:

# hdparm -B /dev/disk/by-label/WD_500G_NTFS
/dev/sdb:
HDIO_DRIVE_CMD(identify) failed: Invalid argument

edit1: (17.12.2011)
-added information regarding different kernel versions.

External usb hdd WD Elements - avoid spindown

Update: I got a new workaound here: External usb hdd WD Elements - avoid spindown -- #2

I've got an external 2.5", 500G USB HDD from WesternDigital
- this one: http://images.google.com/images?q=WDBABV5000ABK-00.
Without being accessed, it spins down after 5-10s (seconds, not minutes!) automatically.
This behavior seems to be hardcoded in the hardware/firmware by WD and cannot be changed (if anyone knows better, please leave a comment). It can be very annoying, for example when starting a file manager or open a 'save as...'-dialog etc. because the hard drive has to spin up every time adding a delay of some seconds until the dialog appears. The same happens when reading or writing at a low speed (let's say ~ <10KiBytes/s) - the drive spins up and down multiple times a minute.

A dirty workaround is to keep the drive busy by touching and syncing in a short interval.

A quick way to do this via commandline:

while [ 1 ]; do echo "touch at - `date`"; touch /media/WD_500G_NTFS/tempfile; sleep 5s; sync; done

A bit nicer with the following script:


edit: inserted link to new post.