External SSD Formatting Advice

Discussion in 'iMac' started by cb3, May 17, 2019.

  1. cb3, May 17, 2019
    Last edited: May 17, 2019

    cb3 macrumors regular

    Joined:
    Jun 5, 2017
    Location:
    Texas
    #1
    Looking for external formatting advice: 2019 iMac, Samsung 1TB T5 external SSD

    I've never uses an external SSD for storage. Should I ...

    1. Leave formatting alone as Samsung has it.
    2. Should I reformat with APFS or Mac Extended Journaled.

    What going to give me the most reliable experience?

    Thanks!

    Edit:
    Also forgot, anyone ever experience sleep issue with the drive and any of this formats

    Edit 2:
    Plan on using for storage of files I'm working on - photos, home videos, work file (graphic design), office app files, etc. Will not be using this for back-ups aka Time Machine.
     
  2. theluggage macrumors 68040

    Joined:
    Jul 29, 2011
    #2
    If you ever want to use the drive on a PC - keep as is (probably exFAT)
    If you ever want to be able to read the drive on OS 10.12 or earlier - reformat as Mac Extended Journaled
    If you want to use the disc as a Time Machine backup - reformat as Mac Extended Journaled
    If none of the above is a concern, reformat as APFS.
     
  3. cb3 thread starter macrumors regular

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    Location:
    Texas
    #3
    Thanks so much. Appreciate your feedback.

    >
     
  4. mikehalloran macrumors 65816

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    Oct 14, 2018
    Location:
    The Sillie Con Valley
    #4
    Do not install an OS onto this external. You will lose the ability to access the Recovery partition and use APFS Snapshots, an extremely quick recovery tool available in High Sierra and Mojave unless you disconnect the drive first.

    An X5 is overkill for Time Machine but will certainly work and you do need to follow the above formatting guideline if you do.
     
  5. cb3 thread starter macrumors regular

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    #5
    Thanks! I'm learning.
     
  6. cynics macrumors G4

    Joined:
    Jan 8, 2012
    #6
    Samsung drives marketed for multiple OS's are usually pre formatted exFAT. MacOS, Windows and with minimal effort most Linux distros (been a while so probably supported out of the box now) have full read-write capability.

    If the drive will ever been hooked to a Windows PC that will need to access the files exFAT is your best bet.

    Even if you will only ever use MacOS I would consider HFS+ if you want to be Apple centric. APFS is find but its has limited Mac compatibly (newer versions of MacOS) and maybe unnecessary for your needs.

    FAT32 is a 4gb file size limitations so not great for media. NTFS is a windows format so that's not an options right out of the gate.
     
  7. zerozoneice macrumors regular

    Joined:
    Jun 26, 2013
    #7
    i'm looking at the same T5 SSD solution for an upcoming 2019 5K imac.
    i'm thinking of getting the top model, with nothing BTO, so meaning 2TB Fusiondrive.
    I need to run bootcamp, but as we know, windows will run off 7200rpm HDD only. Can i install Windows on the external T5 SSD using bootcamp assistant?

    I really don't want to open my new imac right away, break the fusion and replace the HDD with the 850EVO from my old PC :)
     
  8. Fishrrman macrumors P6

    Fishrrman

    Joined:
    Feb 20, 2009
    #8
    If you are going to store "Mac stuff" on the drive, format it to a Mac formatting scheme.

    That would be either HFS+ or APFS.

    I recommend HFS+ (Mac OS extended with journaling enabled, GUID partition format).

    Then... just use it.
     
  9. smirk macrumors 6502a

    smirk

    Joined:
    Jul 18, 2002
    Location:
    Orange County, CA
    #9
    Just to clarify, did you mean that he shouldn't install macOS onto the drive if it's formatted with a non-Apple file system, or is there something about the T5 or USB connection that isn't good for installing macOS on?
     
  10. mikehalloran, May 20, 2019
    Last edited: May 20, 2019

    mikehalloran macrumors 65816

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    Location:
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    #10
    I didn't say either.

    The only way to access the Repair partition in High Sierra/Mojave is boot with the Command r keys held down. You cannot access the Repair partition on an APFS formatted drive if there is a second Mac OS anywhere on a system. Besides the basic repair/recovery tools including change password, interned recovery and others, there is an extremely powerful tool called APFS Snapshots that can restore your entire boot drive to a previous state in a few minutes.

    If booting from your internal drive and there's an OS installed on your external, you must disconnect the external before Command r. Ok. Easy enough. I do this all the time as my test drives have different OS installed.

    Say you bought an X5 and plan to boot from it because you want to get away from the HDD/FD performance of an iMac so equipped. Not a bad plan. However, if you need the Repair partition, you are out of luck as long as there's an OS on the internal drive.

    As to your question, there's a different issue entirely. If booted from a non-APFS formatted drive, you cannot access an APFS drive—this was true in High Sierra but I've not tested it in Mojave yet. APFS drives can see and access externals. Although there are often permission and privilege problems with ExFAT, that's a completely different issue.
     
  11. smirk macrumors 6502a

    smirk

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    Location:
    Orange County, CA
    #11
    Ah, now I understand. Thanks for the clarification and all the good info!
     
  12. miqui macrumors newbie

    miqui

    Joined:
    Sep 11, 2018
    #12
    Also, it turns out there are significant differences in performance depending on format and connection used. I've just checked with my T5 2TB.

    It's formatted in HFS+ since in APFS it was slower.

    Generally, my Samsung T5 SSD, 2TB:
    HFS+: R: ~519 MB/s | W: ~480MB/s (USB-C to USB-C)
    HFS+ encrypted: R: ~499 MB/s | W: ~430 MB/s (USB-C to USB-C)
    HFS+ encrypted: R: ~410 MB/s | W: ~396 MB/s (USB-C to USB-A 3.1)
    APFS encrypted: R: ~420 MB/s | W: ~380 MB/s (USB-C to USB-C)


    So HFS+ and USB-C to USB-C seems to be the best option.
     
  13. cb3 thread starter macrumors regular

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    Jun 5, 2017
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    Texas
    #13
    Thank you all for your advice! Appreciate your time.
     
  14. Lee_Bo macrumors regular

    Lee_Bo

    Joined:
    Mar 26, 2017
    Location:
    Greenville, SC
    #14
    However, if you are also planning on using that same drive as a storage drive and using backup software on that drive, the backup software may not work. Backblaze, for example, will not backup any Time Machine partitions.
     

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13 May 17, 2019