Prevent HDD from sleeping when PC is on and powered?

Question

My Laptop has an addition HDD, that after some time of non usage, gets into sleep mode, or some kind of low power usage. This is very noticeable, due to the lag that happens when I just starting using it again, and by its spinning sound.

I understand that this is a good future when on battery, but I want it to be always ready for use when I have power connected. I did corrected all options in power management for that, but it still gets into sleep after some ideal time.

Answer 1

This is something that is controlled by the drive's firmware so it's not possible for the OS to directly control it. The idle sleep time will vary depending on how the drive is marketed (e.g. NAS drives will have a higher idle time threshold I believe). It's something to watch, as each drive is rated for a certain number of head loads/unloads so you can quickly exceed that value if your idle time does not fit your use case.

A problem like this occurred with WD Green Power Drives:

The problem is this: The Green Power is designed and marketed as a "green" drive, where power efficiency is the primary engineering concern. As part of this concern, the drive is designed to unload the read/write heads after approximately 8 seconds of inactivity. That in itself is not a bad thing — in fact, it's a common attribute of notebook drives, which have different reasons for saving power (battery life). However, certain software (notably, SpeedFan and some distributions of Linux) can cause issues because they access the drive regularly every 10 seconds or every minute or so. This causes a cycle of rapid loading and unloading that is stressful to the drive — far more stressful than "ordinary" use in which the drive is either working steadily or completely idle. http://www.silentpcreview.com/Terabyte_Drive_Fix

Depending on the manufacturer (which you don't state), you might find they have a utility to change some low-level settings like the idle time before the HDD sleeps. WD for sure has software like this, and I'd be surprised if other manufacturers didn't.