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Second External Drive Keeps Dropping Off

1242 Views 25 Replies Latest reply: Jul 24, 2012 1:44 PM by WZZZ RSS
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OzziesMAC Level 2 Level 2 (150 points)
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Jul 18, 2012 2:03 PM

I have two external G-Drives daisy chained together via firewire 800 and each have their own power plug.  They show up on finder as Drive A and Drive B.

They normally spin down when not accessed and spin up as needed.  It appears that when I wake up the Mac from sleep mode, Drive B

is dropped off and Drive A is still on finder.

 

The only way to get drive B to show up again is to power it off then back on.  Is there anyway to correct this?

iMac 27, Mac OS X (10.6.8), 2.8Ghz Intel Quad Core i7 / 8GB / 1TB
  • baltwo Level 9 Level 9 (59,150 points)
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    Jul 18, 2012 2:25 PM (in response to OzziesMAC)

    I never sleep my iMac or its HDs, just the display. Give that a shot and see if the problem goes away.

    27" i7 iMac 10.6.8, Mac OS X (10.7.4), G4 450 MP w/Leopard, 9.2.2
  • baltwo Level 9 Level 9 (59,150 points)
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    Jul 20, 2012 11:03 AM (in response to OzziesMAC)

    I've never replaced an ext HD. Do note, however, that if I'm not using them to update my bootable clones, I usually shut them off. I don't use TM or have any need for additional storage, since I don't collect photos, movies, or music. BTW, I have also disabled putting HDs to sleep.

    27" i7 iMac 10.6.8, Mac OS X (10.7.4), G4 450 MP w/Leopard, 9.2.2
  • WZZZ Level 6 Level 6 (11,875 points)
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    Jul 20, 2012 11:13 AM (in response to baltwo)

    But haven't I read that you had to replace an Internal? Unrelated to keeping it spinning 24/7? I know there's wear and tear from spinning up and down, heads parking etc., but aren't most drives rated to 50,000 spin up/down cycles? Would four or five such cycles a day be all that harmful? Not to mention the constant heat.

     

    In other words, I'm curious to know your rationale for never sleeping.

  • baltwo Level 9 Level 9 (59,150 points)
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    Jul 20, 2012 11:26 AM (in response to WZZZ)

    Yes, the 1 TB internal on my 27" iMac went south, without any warning, not an uncommon issue with a small batch of the OEM ones from Seagate. However, the one on my mate's 24" iMac has been running w/o issues the past five years and it also runs 24/7. When inactive, there's no indication that the HD's writing or reading. Normally not awake for the machine's maintenance functions. Primary reason for electromagnetic devices to fail is the power surge at start up and the resultant warming up to a satisfactory operating temperature. Akin to light bulbs failing on startup, but not when constantly burning. Pondini offers this: http://pondini.org/OSX/Sleep.html for consideration.

    27" i7 iMac 10.6.8, Mac OS X (10.7.4), G4 450 MP w/Leopard, 9.2.2
  • WZZZ Level 6 Level 6 (11,875 points)
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    Jul 20, 2012 11:45 AM (in response to baltwo)

    Primary reason for electromagnetic devices to fail is the power surge at start up and the resultant warming up to a satisfactory operating temperature. Akin to light bulbs failing on startup, but not when constantly burning.

    Hmm, I've heard that one before, but I'm skeptical. And not sure the light bulg analogy is really suitable. Even shut down, if still connected to power, there's trickle current going to  the hardware, if I'm not mistaken. Anyway, there are posts from people who've shut down at night for ten years straight who've had no problems and then from users like you who swear by the opposite. A lot of this is just too anecdotal. I still need to see convincing statistics; and I don't think there are any.

     

    And even if you're right about the startup power surge and temperature jolt to the drive, you'd still have to weigh in the possible negative of too much heat, too much of a good thing by never allowing it to sleep. Must also depend on ambient room temp. It was just 103 here (90+ inside) and I don't think I would have been helping the hardware last by not allowing the computer to sleep under those conditions.

     

    Apple's recommendation to only shut down if the computer won't be used for a length of time and sleep otherwise is based more on the convenience  factor. There's nothing in there about what's better for hardware.

     

    Anyway, different strokes etc. Not something that will ever be settled definitively one way or the other. Probably a lot depends on the luck of the draw.

     

    Btw, Seagate's are getting a reputation lately for being pretty crappy.

  • WZZZ Level 6 Level 6 (11,875 points)
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    Jul 20, 2012 11:56 AM (in response to OzziesMAC)

    Sleeping will be the coolest (and shutdown won't be any cooler.) The next best as far as heat is concerned is to sleep the display (Ctrl-Shift-Eject), which removes the heat coming from the display. The fans keep running.

     

    Most drives' upper temp limit is around 55C, but 45+ and things start to get somewhat concerning. I don't like to  see the drive running for too long in the upper 40s.

     

    http://www.codinghorror.com/blog/2006/12/hard-drive-temperatures-be-afraid.html

     

    And there's smcFan Control.

     

    http://www.eidac.de/

  • WZZZ Level 6 Level 6 (11,875 points)
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    Jul 20, 2012 12:47 PM (in response to OzziesMAC)

    Baltwo probably won't agree, but, depending on room temperature, I don't think it's great news for the hardware to never let the computer sleep. Just my opinion and you're bound to find other ones.

     

    But why don't you monitor the temps for a while set like that and post back with them--in Celsius please.

     

    http://www.islayer.com/apps/istatpro/

     

    Btw, with that setting to allow the drives to sleep when possible, I would have thought the externals would spin down. Or, their internal firmware isn't allowing that to happen and that setting is irrelevant for the externals. But that setting should allow the internal to spin down, which might not be bad for the drive if you're never letting the computer sleep.

     

    Why those settings, which include allowing drives to sleep when possible, are keeping the second external from spinning down I have no idea.

  • baltwo Level 9 Level 9 (59,150 points)
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    Jul 20, 2012 12:49 PM (in response to WZZZ)

    I don't. I don't need any ext HD available when the displays sleeping, so these are my settings. Also, the temps are when fully operating. I've never bothered to capture them after the display slept overnight, since these are benign.

     

    eng svr.png.

     

    Temps for 27%22 iMac.png

    27" i7 iMac 10.6.8, Mac OS X (10.7.4), G4 450 MP w/Leopard, 9.2.2
  • baltwo Level 9 Level 9 (59,150 points)
    Currently Being Moderated
    Jul 20, 2012 2:47 PM (in response to WZZZ)

    Follow up on the iMac HD replacement. I had mine done on 4/16 and Apple finally issued a recall on 7/22: http://www.apple.com/support/imac-harddrive/

    27" i7 iMac 10.6.8, Mac OS X (10.7.4), G4 450 MP w/Leopard, 9.2.2
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