External Hard Drives As Primary Drive

Discussion in 'iMac' started by Dpock, Jan 23, 2012.

  1. Dpock macrumors member

    Nov 4, 2011
    (My initial post on my failing hard drive--now confirmed--is sort of in the way where I hope to go in terms of remedy, hence this post):

    My 2007 24” iMac recently suffered an internal hard drive failure, confirmed by DiskWarrior. Everything else on the iMac seems to be functioning (graphics card, logic board). Rather than install a new internal hard drive (which could be subject to heat stresses and fail) another optioned mentioned was getting an external hard drive as my drive/boot source (ignoring the internal failed hard drive completely) connected to the iMac via a SATA USD docking station. If that’s a doable option I’m all in favor of it.

    I’m wondering if someone could walk me through the steps--Do I just buy the dock and new external hard drive, connect them together, plug it into the iMac and boot it using the option key so I can pick the new external drive? Or will the new drive need to be formatted first? (and how would I do that without a functioning Mac?). I’m assuming if the iMac recognizes the new drive I’ll be able to install the OS onto it, make it the boot disk, and have it run as before. Is that pretty much it?
  2. blueroom macrumors 603


    Feb 15, 2009
    Toronto, Canada
    Why not just install a new HDD into the iMac? They'll be much faster than an external Firewire drive (USB would be awful). iFixIt.com shows how. Not too tough.

    An SSD won't suffer from heat stress.

    And yes you can install OSX on an external drive, it'll work fine albeit slower than an internal.

    Edit, a nice drive that's not too expensive but needs a bracket would be a Seagate Momentus XT 750. It'll run cool.
  3. Dpock thread starter macrumors member

    Nov 4, 2011
    I decided to go with the slower performance option of an external drive due to reading the amount of failures on replacement hard drives (internal) users are experiencing in 24" iMacs from '07/08'. Maybe down the road I'll put in a new internal HD but for now I just want the steps I outlined above confirmed so I can go ahead and buy the dock and new hard drive.
  4. Dpock thread starter macrumors member

    Nov 4, 2011
  5. Mr Rogers macrumors regular

    Oct 24, 2003
    Hong Kong
    All my computers are currently run from FW800 enabled 3T WD Externals, indeed, I've not run from an internal HDD on my iMac's or Mac Mini for more than two years - to date, I've had no issues apart from the external itself failing - hence, all my externals are mirrored to avoid loss of data.

    Hope this helps, but, a large external used as a boot drive seems not to slow down my own work and is a much cheaper option than buying a upgraded BTO iMac or, installing a bigger HDD/SSD into a iMac.
  6. derbothaus macrumors 601


    Jul 17, 2010
    You end up loosing 60MB/s each way for current HD's. FW also sleeps itself quite a bit, so waiting for spin up is lame. FW chipset runs hot as well, every Mac I have owned gains 5-10ºC when FW is active. There is added processor overhead too. It should be seen as a bandaid not a solution. Only external for boot "all-the-time" I would consider would be Thunderbolt as I don't know if it suffers from the other external link negatives. It is definitely fast enough.
  7. Dpock thread starter macrumors member

    Nov 4, 2011
    Thanks for the quick feedback.

    With a failed HD in my iMac (but which seems to still boot to the install discs okay, and Diskwarrior), would it recognize the plugged in Seagate external drive by holding the option key down on start up (so I could install my OS into it and make it the boot drive)?
  8. derbothaus macrumors 601


    Jul 17, 2010
    You may have to format it in Disk Utility to HFS+ Extended Journaled. If it is new they usually ship NTFS for Windows. After that it will be available as any Disk. For storage or to point an installer to.
  9. Dpock thread starter macrumors member

    Nov 4, 2011
    Anyone want to recommend a firewire dock they've used, and best brand for 500gb external HDs?
  10. Sandman1969 macrumors 6502a


    Nov 5, 2007
    I use this for my Time Machine and Backup drive.

    I like how it looks like a Mac Pro. Supports USB2, FW400, FW800, and eSata.

    Not sure on best drive. I just took my WD out of my failed Time Capsule and put in there.

    If your iMac is out of warranty I would go with replacing the internal. It isn't that hard to do. I replaced my sister-in-laws, white IMac's and it wasn't bad at all. In fact I think they are more involved than the 2007 since you have to take a bunch of screws to get the front case off. 2007's you just suction cup off the glass to get to that point.
  11. Dpock thread starter macrumors member

    Nov 4, 2011
    Will a SATA external hard drive connected via a dock/firewire work with my 2007 imac, which came with a serial ATA internal hard drive (now dead)?
  12. Riverrun macrumors regular

    Jul 11, 2007
  13. Dpock, Jan 26, 2012
    Last edited: Jan 26, 2012

    Dpock thread starter macrumors member

    Nov 4, 2011
    I've got a new external mac compatible HD plugged in and I'm trying to install the OS onto it--the dialogue says "can't use this disk as start-up disk". So how do install the OS onto it?

    EDIT: Dialogue says "You cannot install Mac OS X on this volume. Mac OS X cannot start up from this volume."
  14. torana355 macrumors 68030

    Dec 8, 2009
    Sydney, Australia
    You need to format the drive as GUID and Mac OS Extended (journaled) first though disk utility.
  15. Dpock thread starter macrumors member

    Nov 4, 2011
    Thanks. Got it. I seem to have created two titled new volumes--how do I delete the one I don't need?

    EDIT: I guess while I'm at it, how do I make the external HD the boot drive?
  16. snberk103 macrumors 603

    Oct 22, 2007
    An Island in the Salish Sea
    If it's not too late to return your external drive....

    Why not get a new internal drive with a 3 year warranty? If it fails, it'll be covered... and the 3 years will certainly get you well past the point you will be thinking about a new iMac, eh?

    If you are going to go with the external... once you get it installed, you will not notice much difference in speed if it is FW 800. I accidentally set my backup (clone) external HDD as the Start Up drive. Took me a couple of days to notice - duh..... it is an FW 800 HDD.

    Once the OS is installed, there is a Start Up Drive in the Settings. At that is where it is in OS X 10.6.8.

  17. Dpock thread starter macrumors member

    Nov 4, 2011
    After disk one installs the computer restarts but can't find the boot drive so I can install disk two--can I set the new external drive as the boot drive after installing just the first OS disk?
  18. torana355 macrumors 68030

    Dec 8, 2009
    Sydney, Australia
    Hold down option when it reboots and select your external drive.
  19. Fishrrman macrumors G5


    Feb 20, 2009
    "Anyone want to recommend a firewire dock they've used, and best brand for 500gb external HDs?"


    Sorry for the shouting, but there's a high probability that you are NOT going to be able to boot a 2007-vintage iMac from a current SATA/firewire docking station.

    They will boot just fine from USB, but firewire -- no deal.

    I can offer personal experience. I have a 2007-vintage "white" Intel iMac that will boot from my Other World Computing Voyager USB3/firewire SATA dock -- but ONLY via USB. Connect with either firewire 400 or 800, and the Mac does not "see" the dock as a bootable device.

    This seemed illogical to me, but after a bit of research I uncovered a post _somewhere_ from someone in a similar situation, who had contacted OWC tech support, and the tech support guy confirmed that their docks wouldn't boot "older" Macs via firewire (only newer ones).

    It might be possible to find an _older_ firewire 400 (only) dock that might work. I have a _hunch_ that when these devices were "upgraded" to handle firewire 800 as well as 400, something internally (the controller chip?) got changed to where they won't be visible as boot devices to earlier Macs. Or -- it may have been some kind change within the Mac hardware or even the Mac OS itself.

    So... it's probably not worth spending the money on a firewire docking station UNLESS you plan to upgrade your Mac at some time in the future. I'd save the money and get a cheap USB/SATA dock instead, some can be bought for as little as $20.
  20. Dpock, Jan 27, 2012
    Last edited: Jan 27, 2012

    Dpock thread starter macrumors member

    Nov 4, 2011
    Once booted, would it use the Firewire connection? Or stick with the USB 2.0?

    EDIT: The mac was purchased late October, 2007 and has an aluminum case. It's a 2.8 Ghz Intel Core 2 Extreme. Came with a 500GB Serial ATA drive.
  21. Dpock thread starter macrumors member

    Nov 4, 2011
    Project Abandoned

    Apparently (as Fisherrman suggests) an external SATA HD firewire connected to a late 2007 iMac does not work (is not recognizable to the iMac) as a boot drive.

    I'm going to go with the bulk of advice and have a new HD installed instead. If anyone can recommend a good, cheap, cool running 500GB drive I'd appreciate it.
  22. Davidgarcia macrumors newbie

    May 3, 2012
    Trouble with esata

    Hi I own a 2010 27"imac and have just purchased a caddy with firewire 800 to be used with a Sata hard drive.

    This is the Hard drive:

    Seagate 3TB 3.5 inch 7200RPM 64MB Cache SATA3 Hard Drive

    When I connected it to the imac I get the following message:

    "The disk you inserted is not readable by this computer"

    Im not sure what Im doing wrong, please help

    Thank you

  23. LaunchpadBS macrumors 6502a

    Nov 11, 2008
    I had the same issue, same drive, took the external enclosure back twice and exchanged for diff manufacturer but not seemed to work with the 3TB drive, my 2TB worked fine.
  24. harddrivefailur macrumors newbie

    May 24, 2012
    Irvine, CA
    I think you probably want to check and see what the hard drive is formatted as. A lot of new external hard drives, formatted automatically in Windows based formats. If this is the case for you, you're going to have to reformat the drive to work with the Mac file system.

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