Is there a way to manually spin down a hard drive from within macOS?

[BondiBlue]

I have a 2011 27" iMac, and it has a failing hard drive. Right now the machine has the stock 1TB Seagate drive (failing) as well as a 500GB Crucial MX500. The SSD is perfectly healthy. Is there some way to manually force the drive to spin down from within the OS? I don't need access to any files stored on the drive. 

[Action_Johnson]

Open it up and take it out, do a fresh install of whatever the latest version of MacOS you can install on the SSD. 

[BondiBlue]

8 minutes ago, Action_Johnson said:

Open it up and take it out, do a fresh install of whatever the latest version of MacOS you can install on the SSD. 

That's not what I asked about. macOS is already installed and running from the SSD. If I was still using the hard drive then I wouldn't even consider finding a way to spin it down. 

[Action_Johnson]

Then just open it up and take it out.

 

If you don't want to do that, go into Disk Utility and just unmount it. 

 

[BondiBlue]

13 minutes ago, Action_Johnson said:

Then just open it up and take it out.

 

If you don't want to do that, go into Disk Utility and just unmount it. 

 

Unmounting the disk does not make it spin down. If I had the time to open it up and pull the drive out then I wouldn't be trying to spin it down while still installed. 

[maplepants]

I think what you're looking for here is to use 

diskutil eject

instead of 

diskutil unmount

 

Unmounting a single volume means the OS could still be using the drive, keeping it available in case you want to mount a different volume. When you eject the disk, that tells macOS that you don't the entire disk or any of it's volumes anymore.

 

Personally, I don't have this use case so I can't guarantee that this will work but it's work trying because it should work.

[BondiBlue]

10 hours ago, maplepants said:

I think what you're looking for here is to use 

diskutil eject

instead of 

diskutil unmount

 

Unmounting a single volume means the OS could still be using the drive, keeping it available in case you want to mount a different volume. When you eject the disk, that tells macOS that you don't the entire disk or any of it's volumes anymore.

 

Personally, I don't have this use case so I can't guarantee that this will work but it's work trying because it should work.

I haven't had any luck, so at this point I'll just try to make time to swap the drive sooner than I planned. It's not hard, but this machine is a little special, so it doesn't go back together super easily. Of note is the optical drive - the display keeps it in place properly.

[Roswell]

On 8/22/2021 at 5:30 PM, BondiBlue said:

Unmounting the disk does not make it spin down. If I had the time to open it up and pull the drive out then I wouldn't be trying to spin it down while still installed. 

Ejecting the drive should let it sleep after some minutes. If it's continuing to spin, there's something else at play.