Boot OS X from external SSD

Discussion in 'iMac' started by varian55zx, Feb 11, 2016.

  1. varian55zx, Feb 11, 2016
    Last edited: Feb 11, 2016

    varian55zx macrumors 6502a

    varian55zx

    Joined:
    May 10, 2012
    Location:
    San Francisco
    #1
    I have an older iMac that I would like to now put OS X on an external SSD and boot from it, along with all the apps on the computer, but (edit: ) accessing everything else on the internal HD of the Mac by changing the system's home folder to that of the one on the internal, thus, in my mind, getting the 'best of both worlds'.

    Strangely, I must be the first person online to ask this question.

    Is this feasible to do? Would I experience all the benefits of the SSD with only having the apps and OS on it while keeping all other files on the internal?

    Should I buy a thunderbolt or USB 3 enclosure? Apparently this is another subject that just nobody knows about, because I see many people saying you can't external boot from USB 3, however, as I understand it, you can. But which is better for this?

    Scary so many people think you can't.

    Is this a feasible plan? Is there a particular SSD that is best suited for this?

    Also, what exactly is TRIM and why would I care?

    Thanks a lot for any help.
     
  2. keysofanxiety, Feb 11, 2016
    Last edited: Feb 11, 2016

    keysofanxiety macrumors 604

    keysofanxiety

    Joined:
    Nov 23, 2011
    #2
    USB SATA 3 dock, save some cash. I'd recommend any Crucial or Samsung SSD, but that's just personal preference as in my experience they don't have any problems.

    Hold CMD+R to boot into Recovery partition with the SSD plugged in via USB. Go into Disk Utility in OS X Utilities. Format SSD through Disk Utility. Click Reinstall OS X. Set to install directly onto the SSD. Sorted.

    Then hold Alt on startup and select the SSD. Hold Ctrl and press Enter so it boots into SSD by default.

    Open Migration Assistant in OS X, transfer all apps/data that way.

    EDIT: if you have an older iMac it's not likely to have USB 3. As such the performance benefits of an external SSD will be negligible. Therefore I'd recommend fitting the SSD inside rather than running externally. You can still install the OS by booting into the recovery partition externally on the old HDD, or you can run through the above instructions then swap out the HDD with the SSD.

    Also depending on the model it may be a 3.5" HDD rather than 2.5" as the SSDs are, so you might need to get an enclosure for it to fit.
     
  3. varian55zx thread starter macrumors 6502a

    varian55zx

    Joined:
    May 10, 2012
    Location:
    San Francisco
    #3
    Thanks, that was a very informative response.

    My only other question is, my intention was to set the home folder of the SSD to the one on the internal, through Users & Groups in System Preferences, thus having access to everything on the internal as if I was booting from it itself.

    However, I wanted to try and get the apps to boot off the SSD, to get the benefit of the SSD speed, thus my reference to having only the apps and OS on there. Is that a realistic thing to do?

    Also, not to worry. It is an older Mac but it has USB 3 and thunderbolt capability. I would be willing to spend more for the thunderbolt, should the difference be very apparent. If the difference is negligible, then I wouldn't see the necessity to pay.
     
  4. Fishrrman macrumors G3

    Joined:
    Feb 20, 2009
    #4
    It's trivially easy to boot and run a Mac from an "external booter".
    I've been doing it for years.
    Almost nothing to it (I said, "almost").

    Fastest, easiest, cheapest way is to get something like this:
    http://www.amazon.com/exec/obidos/ASIN/B00ZTRY532?tag=delt-20

    Just plug it in, use a cloning app like CarbonCopyCloner or SuperDuper to "clone over" your OS, apps, and accounts.
    You'll be back to booting and running in about 10 minutes.

    Or, buy a "bare" 2.5" SSD of your choice, and a USB3 enclosure such as this:
    http://www.amazon.com/MiniPro-Exter...8-1&keywords=oyen+digital+2.5"+usb3+enclosure

    Put the drive into the enclosure, connect it, initialize it, clone to it, ready to go.

    Be aware that you can't use TRIM when connecting via USB.
    Some will claim that it will slow down the drive as time goes by, but I've been booting and running my Mac Mini via an SSD in a USB3 enclosure for three years now, without any perceptible speed differences at all.
    It just works.
     
  5. varian55zx thread starter macrumors 6502a

    varian55zx

    Joined:
    May 10, 2012
    Location:
    San Francisco
    #5
    Thanks a lot, that was very helpful.

    My only question though is how can I boot from the external ssd, while keeping all other data on the internal? Is that achieved by changing the home folder in Users & Groups?
     
  6. hfg macrumors 68040

    hfg

    Joined:
    Dec 1, 2006
    Location:
    Cedar Rapids, IA. USA
    #6
    I believe that is the Apple recommended way to do what you want to do. I seem to recall that there was a support page on the Apple web site which discussed moving your home folder to another disk and detailed that method.
     
  7. varian55zx thread starter macrumors 6502a

    varian55zx

    Joined:
    May 10, 2012
    Location:
    San Francisco
    #7
    I've seen a lot of threads on that too. I really have no interest in doing that though. I have >600gb of stuff on my internal, I won't be moving that to a tiny SSD.

    I want to have merely OS X and all of my apps on the SSD, in my mind I will have the full benefits of SSD that way. Is there anything else I would need to move over?

    Also, how would I go about running the apps from the SSD while using the home folder of my internal? Is that possible?

    Thank you so much for any help.
     
  8. warvanov macrumors 6502a

    Joined:
    Oct 13, 2011
    #8
    That's exactly what I did on my MacBook Pro the other day and it was a piece of cake to do. I added an SSD as a second internal drive. I installed OSX on the new drive and it gave me the option to import the system configuration, applications, and data. I imported the system config and apps, but not the data. Once I booted up I changed the users and groups preferences to my existing folder on the old drive. Now all my files are on the old 1TB HDD, and all my system and applications are on the new SSD, and everything is configured as I had it before down to the desktop background and dock. Easy peasy.
     
  9. varian55zx, Feb 11, 2016
    Last edited: Feb 11, 2016

    varian55zx thread starter macrumors 6502a

    varian55zx

    Joined:
    May 10, 2012
    Location:
    San Francisco
    #9
    Man, thank you so much.

    This was EXACTLY what I was wondering, not only how to do it, but also if it was easy. Thank you so much, man! I'm totally sold on this idea. I'll be doing the exact same thing you did, but with an external drive.
     

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