How to use external HDD as extended storage?

Discussion in 'macOS' started by Tarek, Feb 24, 2018.

  1. Tarek macrumors 6502

    Jun 25, 2009
    Liverpool, UK
    Hello there

    I recently bought an external HDD for my MacBook Pro because it is only a 256GB model so it doesn't have a lot of space.

    I read online that I can use the external HDD not only as a Time Machine drive, but also for general file storage. I tried following the methods posted about formatting the drive as Mac OS Extended (Journaled) and then partitioning it into two partitions, but I am unable to do that.

    Please check the screenshot attached for reference.

    I am currently reading on how to convert an external HDD from MBR to GUID, but is that the answer to this?

    Thanks for your time.

    Attached Files:

  2. DeltaMac macrumors G3


    Jul 30, 2003
    Yes, changing the partition map from MBR to GUID is your answer.
  3. Tarek thread starter macrumors 6502

    Jun 25, 2009
    Liverpool, UK
    @DeltaMac Thanks for your reply. How would I go about doing that? I tried using the "gpdisk" commands but they didn't work.
  4. Fishrrman macrumors P6


    Feb 20, 2009
    Better solution:

    First, erase the external drive to Mac OS extended with journaling enabled.

    Then, PARTITION it.
    Make the first partition the size of your internal drive -- 256gb
    Make the second (and/or third) partitions whatever size you require.

    STOP using Time Machine.
    Instead, use either CarbonCopyCloner or SuperDuper to create a FINDER-BOOTABLE cloned backup of your internal SSD.
    Both of these are free to download and try for 30 days.

    Now you have a SECOND BOOT SOURCE with "all your stuff already on it".
    If you ever get into an "I can't boot!" moment, you'll discover how important this can be.
  5. Tarek thread starter macrumors 6502

    Jun 25, 2009
    Liverpool, UK
    @Fishrrman Thank you for your reply. I've never used Time Machine before so I am not sure how reliable it is, however I just downloaded Carbon Copy Cloner in order to give it a shot and see how it works.

    I was able to use Windows and an application called EaseUS Partition in order to change my external hard drive's scheme from MBR to GPT, and then I booted back into Mac and used Disk Utility to create a 350GB partition for Mac Backup and the rest of the 2TB for general file storage.

    I am currently in the process of cloning my Macintosh HD partition to my external HDD, hopefully the process finishes smoothly.

    Since CCC is only a trial, will I actually be able to use the finder-bootable cloned backup regardless of the registration and trial status, right? The problem is that I cannot do scheduled backups unless I actually purchase it, but I am not sure if I should pay the 30 pounds or just use Time Machine.

    Why do you think Time Machine isn't as good as the other two? Is it because it doesn't create a bootable clone/backup that I can use if the OS fails?
  6. Clix Pix macrumors demi-goddess

    Clix Pix

    Oct 9, 2005
    8 miles from the Apple Store at Tysons (VA)
    I see you've already done something, but for future reference, adding more details to what Fishrrman has said: when in Disk Utility, in the upper left corner, click on "view" and when the menu opens, click on "show all devices." Then when you highlight the main drive, you will have the choices of naming the drive, formatting the drive to Mac OS Extended [Journaled] and setting the Scheme to GUID Partition Map. Then click "erase" and the drive will be appropriately reformatted. No need to be mucking around in some Windows program -- AAGGH!!!

    I do not think it is a good idea to have Time Machine or any backup on the same external drive along with other storage. External drives can fail, too, you know..... A better solution would be to buy another external drive and use one solely for the purpose of backups and the other for the purpose of supplementing the computer's internal drive. For one thing, the general rule of thumb is to have the backup drive with at least twice the capacity of the internal drive. In making a partition of only 350 GB for Time Machine, that is likely to create problems in the future. Drives do fill up eventually over time, even with incremental backups.

    I've never been a big fan of Time Machine, as it can be quirky, and, right, as you state, it does not create a bootable clone/backup. Also, both SuperDuper and CarbonCopyCloner are more flexible and offer more options in how you want to handle backups.

    The way I manage backups, storage and so on is to have external drives devoted solely to backups and archiving, and other drives for what I term "supplementary" drives; the latter are external SSDs which hold all the stuff I want easily available but which does not need to be in my computer itself. I can plug in one of those external SSDs and retrieve or look at any file or image almost as quickly as I could if it were still on the machine's internal SSD. When I do monthly backups I first back up what's on the machine, and then I take off anything that accumulated during the month that I might not really need to keep on the computer, and stick that into the supplementary drives, which are incremental. I back up the supplementary drives as well, so that nothing gets lost. Yes, this system necessitates multiple external drives, both "spinner" ones and SSDs; fortunately prices on external drives are fairly reasonable for "spinner" drives and eventually will be coming down on external SSD drives as well.
  7. Fishrrman macrumors P6


    Feb 20, 2009
    OP asked:
    "Since CCC is only a trial, will I actually be able to use the finder-bootable cloned backup regardless of the registration and trial status, right?"

    Yes, the backup will always be bootable, whether you are still running CCC or not.

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6 February 24, 2018