6 ms·

Isn't spin down controlled by the host and not the drive?

by pedrocr 13y ago

jzwinck 13y ago
Some drives like WD's Green series have variable RPM to save power (and therefore heat). I don't think the OS is involved at all with controlling how fast those disks spin (so long as they are spinning at all).
- nknighthb 13y ago
  WD's marketroids tried very hard to give people that impression, but it's false. http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771438.pdf http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771... At the very bottom, in small, grey text, you'll find "IntelliPower" defined as: "A fine-tuned balance of spin speed, transfer rate and caching algorithms designed to deliver both significant power savings and solid performance. For each WD Green drive model, WD may use a different, invariable RPM."
cnvogel 13y ago
The host can spin down a drive manually, but most often it's done autonomously be the drive. ‣ In Linux you can manually ... • check the power state of your drive using: hdparm -C /dev/sda • manually spin down the drive (standby) using: hdparm -y /dev/sda (it will immediately spin up at the first attempt to read a sector) ‣ Or you configure the automatic standby of the drive (which also does not involve the OS)... • hdparm -S n /dev/sda will configure the timeout of the drive to a value encoding the time to spin-down on a non-linear scale, check the manpage • hdparm -B n /dev/sda will configure another type of power management which doesn't specify a fixed timeout, but rather a vendor-defined type of arbitrary power saving measures on a scale of 1..254 (1: waste power, 254: conserve power, n>128 allows spin down) The latter two options are handled internally by the drive and (as far as I know) even stored non-volatile. http://linux.die.net/man/8/hdparm http://linux.die.net/man/8/hdparm (Edit: fixed my broken English ;-) )
- Filligree 13y ago
  So, actually you got -B backwards. n < 128 allows spin-down.

Isn't spin down controlled by the host and not the drive?

by pedrocr 13y ago

Isn't spin down controlled by the host and not the drive?

Some drives like WD's Green series have variable RPM to save power (and therefore heat). I don't think the OS is involved at all with controlling how fast those disks spin (so long as they are spinning at all).

nknighthb 13y ago
WD's marketroids tried very hard to give people that impression, but it's false. http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771438.pdf http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-771... At the very bottom, in small, grey text, you'll find "IntelliPower" defined as: "A fine-tuned balance of spin speed, transfer rate and caching algorithms designed to deliver both significant power savings and solid performance. For each WD Green drive model, WD may use a different, invariable RPM."

cnvogel 13y ago

The host can spin down a drive manually, but most often it's done autonomously be the drive. ‣ In Linux you can manually ... • check the power state of your drive using: hdparm -C /dev/sda • manually spin down the drive (standby) using: hdparm -y /dev/sda (it will immediately spin up at the first attempt to read a sector) ‣ Or you configure the automatic standby of the drive (which also does not involve the OS)... • hdparm -S n /dev/sda will configure the timeout of the drive to a value encoding the time to spin-down on a non-linear scale, check the manpage • hdparm -B n /dev/sda will configure another type of power management which doesn't specify a fixed timeout, but rather a vendor-defined type of arbitrary power saving measures on a scale of 1..254 (1: waste power, 254: conserve power, n>128 allows spin down) The latter two options are handled internally by the drive and (as far as I know) even stored non-volatile. http://linux.die.net/man/8/hdparm http://linux.die.net/man/8/hdparm (Edit: fixed my broken English ;-) )

Filligree 13y ago
So, actually you got -B backwards. n < 128 allows spin-down.