Hard drive load cycles? (Is it safe to let the HDD spin down all the time?)

Discussion in 'macOS' started by Cloudane, Oct 31, 2007.

  1. Cloudane macrumors 65816

    Cloudane

    Joined:
    Aug 6, 2007
    Location:
    Sweet Apple Acres
    #1
    Just heard via slashdot about a bug in Ubuntu Linux which causes rapid wear and tear on hard drives, related to the power saving triggering frequent "load cycles". Full explanation here:

    http://www.linux-hero.com/rant/explanation-ubuntu-hard-drive-wear-and-tear

    Can anyone with more technical knowledge of the ins and outs of hard drives and OS X's power saving shed some light on whether it's an issue in OS X?

    I'm thinking of how, by default, Macs are configured to "power down the HDD when possible", even iMacs plugged into the mains. Is this something that should be turned off to reduce wear on the drive?
     
  2. mkrishnan Moderator emeritus

    mkrishnan

    Joined:
    Jan 9, 2004
    Location:
    Grand Rapids, MI, USA
    #2
    OS X definitely spins down the drive if the Mac goes to sleep, and also if it's been idle for some time. But stop and think about the report regarding Ubuntu. If I understand what this person is saying correctly, she/he is reporting that the drive in question was spun down and back up 56,000 times in 2.5 months (about 75 days). This means that the drive was spinning down and back up 750 times a day. :eek: As in once every two minutes, 24x7. (As an aside, he/she also states 150 power cycles in 75 days... which, I guess there are some people who actually turn their computer on and off twice a day, but I would hope not too many Mac users really need to do that, and I'm surprised that a lot of Ubuntu users do!)

    Anyway, this is not happening on your Mac. If you use sleep / wake significantly on your Mac, and you let the drive sleep when idle, you might accumulate ... 5-10 cycles a day. At that rate, it would take you approximately 160 years to hit 600,000 cycles.
     
  3. Cloudane thread starter macrumors 65816

    Cloudane

    Joined:
    Aug 6, 2007
    Location:
    Sweet Apple Acres
    #3
    Haha... ok that's fair enough then :) I didn't quite understand what was being said in the article. I thought if it was maybe spinning down after 10 minutes idle and there was something fairly light being done such as web browsing it could be up and down a fair few times per day.... but it's obviously not as bad as that bug.

    Thanks for the explanation.
     
  4. Veri macrumors 6502a

    Joined:
    Sep 23, 2007
    #4
    Use smartmontools to monitor spin-up count, and other interesting things: smartctl -a /dev/disk0 will suffice for the first drive. Use APM Tuner X if you find defaults/OS configuration too aggressive; I had to do this for a WD I shoved into an old Powerbook Wallstreet running Tiger. Another symptom is click every minute or two as the heads park.
     
  5. machd macrumors newbie

    Joined:
    Sep 8, 2007
    #5
    what about with time machine? my external now spins up and down a lot more then i remember because of time machine. is it putting a strain on my drive?
     

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