differences between Spinning down 3.5″ HDD vs. spinning down a 2.5″ HDD?

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Problem :

I’m using a simple USB to Sata/IDE adapter to connect a sata drive to Raspberry Pi2 running OSMC. (the adapter you can get on ebay for a couple of dollars)

When I have a 2.5″ laptop HDD connected, I can spin it down with no issues using

sudo hdparm -y /dev/sda 


sudo hdparm -Y /dev/sda

when I have a 3.5″ PC HDD connected, I can’t get it to spin down. still getting the proper respond:

sudo hdparm -Y /dev/sda

 issuing sleep command

but the HDD won’t spin down!
for the sake of it, I have also tried with hd-idle and sdparm (for reference – I used this manual)

(btw Power is from an external power supply)

Actually, I was really surprised when the 2.5″ drive did spun down, because I’m really trying to get the 3.5″ to spin down, and I was thinking that the usb to sata adapter wasn’t sending the spindown command properly to the drive. (not translating it correctly from USB to SATA.

kind of lost here!

Solution :

I’m looking at the: hdparam

and at this section:

Query/set Advanced Power Management feature, if the drive supports it. A low value means aggressive power management and a high value
means better performance. Possible settings range from values 1
through 127 (which permit spin-down), and values 128 through 254
(which do not permit spin-down). The highest degree of power
management is attained with a setting of 1, and the highest I/O
performance with a setting of 254. A value of 255 tells hdparm to
disable Advanced Power Management altogether on the drive (not all
drives support disabling it, but most do).

So it looks like that this might be related to Advanced Power Management feature of the drive.

You can try to query that value with:

sudo hdparm -B /dev/sda

And change it if needed with:

sudo hdparm -B127 /dev/sda

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