Mac Mini DIY Fusion drive - HDD spinning down ?

Discussion in 'Mac mini' started by robsonj1, Feb 9, 2014.

  1. robsonj1 macrumors newbie

    Feb 9, 2014
    I've a Mac Mini 2012 and have recently added a second drive and created a 'Fusion' volume with a 256 SSD and a 1TB WD HDD. Everything is working fine except that I can hear the HDD spinning down every few minutes, and then after about five seconds it spins back up again.

    I was under the impression that the HDD should be spinning constantly in a Fusion drive ? I'm worried that I'm going to reduce the live of this drive considerably by having it spinning up/down all the time.

    Does anyone know a way I can keep this drive spinning ? I've changed the System Preferences - Energy Saver - Put Hard drives to sleep when possible but it doesn't make any difference.

    The drive is a Western Digital 1TB 'Blue' drive (WD10JPVX).

    I'm thinking there might be a utility out there that could alter some SMART setting or other on the drive to keep it spinning.

    Would be very grateful to hear from anyone with any ideas!

  2. chrfr macrumors 604

    Jul 11, 2009
    This is how it should work. I'm surprised you can hear it, though. In any case, I wouldn't worry.
  3. Fishrrman macrumors P6


    Feb 20, 2009
    You might go to system prefences, and then look at the "energy saver" pane.

    Does "Put hard disks to sleep when possible" have a checkmark in it?

    If it does, UNCHECK that box, close system prefs, and see what happens.
  4. robsonj1 thread starter macrumors newbie

    Feb 9, 2014
    I just wanted to post an update to my original query in case my experiences can help others.

    I believe the HDD part of a fusion drive should remain spinning constantly. A fusion drive works at the block rather than file level, so the HDD shouldn't be able to spin itself down unless the entire volume is inactive.

    The original Western Digital Blue drive I was using seemed to be set to have a rather aggressive power saving setting in the drive itself which would cause it to spin down after a few seconds of inactivity. I don't believe this is a good idea for use in any kind of drive array. I avoided the 'Green' drives in case this kind of thing might happen, but it looks like the 'Blue' drive has the same characteristic.

    I've now swapped out this drive for an older 1TB Seagate Barracuda and it doesn't spin down at all now, so I'm not seeing the constant spin up/down cycles and hopefully the drive isn't going to suffer so much wear and tear (and also the waits whilst the drive spins up each time).

    So the moral of this I think is to be careful when choosing the drives to use in a roll your own Fusion array. I really do think it matters to avoid any kind of 'Green' or 'energy-saving' HDD. Best to choose something that is designed to be used in a drive array (ie RAID enclosure etc).

    Hope this helps,
  5. paulrbeers macrumors 68040

    Dec 17, 2009
    Interesting, but let me ask you this: Have you maxed out your SSD? Just curious if OSX would allow the hard drive to spin down if it knowingly knew you weren't going to hit the hard drive....
  6. chrfr macrumors 604

    Jul 11, 2009
    The disk will spin down when the Fusion drive is idle. It'll spin up when there's activity, regardless of whether or not all your data fits on the SSD.

  7. rachalmers macrumors member


    Oct 21, 2012

    Thanks for your comments here. I wish I'd seen the article earlier, like before I purchased the WD Blue. Same as yours. I have it in - had it in, a USB 3.0 External Enclosure and it really didn't like that. It reset my Mini after about 30 minutes. So putting the drive only on a Y-Type USB 2.0 connector allows it to run ok, but it spins up and down every minute of so. Very annoying. Regardless of System Preference settings, regardless of the Macrumors 'keep drive spinning' app.
    So like you - back to the good old Seagate Drives. The non-green types.
    I do have a Seagate Green in my Toshiba laptop that has no problems. It's just this one on the mac mini. (2012)

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6 February 9, 2014