Add partition to an existing HD

Discussion in 'Mac mini' started by rich1812, Sep 28, 2016.

  1. rich1812, Sep 28, 2016
    Last edited: Sep 28, 2016

    rich1812 macrumors member

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    #1
    Hi, I have a 2T HD, set up into two partitions, both partitions have data. Now I would like to add a third partition to the HD.How can I do this without losing any data?

    I have El Capitan 10.11.6, The disk utility app is kinda funky, in the partition tab, the circle of the disk confuses me.

    Thank you in advance
     
  2. Fishrrman macrumors G5

    Fishrrman

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    Feb 20, 2009
    #2
    Really, the best way to do this is to:

    1. Backup the data on BOTH existing partitions to another drive (or drives).
    2. Re-initialize the 2tb HDD
    3. Partition as required.
    4. Re-copy the data from the backup drive BACK TO the respective partitions.
     
  3. rich1812 thread starter macrumors member

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    #3
    Thank you for your reply. But the point is I do not have another 2T HD to back my data to, therefore I would have to operate on the existing 2T HD without destroying any data.
     
  4. Weaselboy Moderator

    Weaselboy

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    #4


    Here is a video that may help you understand.

    You will only be able to add on the third volume by shrinking the existing second volume (partition). You will not be able to resize volume one... only volume two. This will not erase data on either volume one or two.

    Backup first just to be safe though.
     
  5. thats all folks macrumors 6502a

    thats all folks

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    #5
    you should plan for it to destroy your data. you can re-partition a drive but it is a brutal process if there are more than a few files on that drive. entering into this without a ready backup is a bad idea. it can work but it is a far riskier action than most you would ask of a drive. much better to do what Fishrrman offered. and really, two backups of each partition while you are wiping the original.

    and please explain, why do you want this? also, how full is each partition currently?
     
  6. mildocjr macrumors 65816

    #6
    Not really sure why they went with a radial display when the linear display made much more logical sense as to how data is written to disk in a perfectly defragged world.

    I'd say backup your data, then attempt to shrink each partition down to a reasonable size. Keep in mind that it may take a while as data isn't exactly written to disk like 1, 2 ,3 ,4. It writes data based on the most contiguous block for the data

    Once both partitions are shrunk so you can split it in thirds, create your third partition. If you run into snags or data gets wiped, you can always restore from backup. Resizing without initializing is the fastest way to do it, but doesn't always work. But the cleanest way is to initialize then resize, as you get the added benefit of mostly contiguous files.
     
  7. rich1812 thread starter macrumors member

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    #7
    Thank you all for the replies. I figured out how to "steal" a chunk of space from the largest partition to make a third partition successfully without loosing any data.:)
    --- Post Merged, Sep 29, 2016 ---
    The software engineers can be so goddamn annoying. What is the purpose to change a try and proof UI that every user is used to?
     
  8. mildocjr macrumors 65816

    #8
    After considering it for a while, it does seem cooler to have a radial display of used space for the non-technical users.
     
  9. shaunp macrumors 65816

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    Nov 5, 2010
    #9
    What will a 3rd partition give you? I honestly can't understand why you would need to do this. The only time I would partition a disk perhaps for bootcamp, or if I had an app that would fill up the entire disk if it wasn't in a separate partition. Also you say you don't have a second disk to backup on to, so how exactly are you backing up now?

    My advice to you would be to not create another partition, but to definitely get a second disk and schedule a regular backup.
     
  10. rich1812 thread starter macrumors member

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    #10
    My 2T HD is partitioned in this way:
    For quick emergency recovery,
    1 portion is a clone of my Mac mini(500G,)
    1 partion is a clone of the MBA(500G,)
    The third portion is for all data back up.

    Eventually I will get another 2T HD to back up the backup HD
     
  11. shaunp macrumors 65816

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    #11
    Ah, so the 2TB disk is a backup anyway? That makes a difference - thought it was your primary disk. I'd just have a go at resizing the second partition see if you can get a bit of space back for the third one. If it breaks, reclone the machines as you haven't lost the primary copy
     
  12. rich1812 thread starter macrumors member

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    #12
    Thank you for your reply. But did you read my previous posts? The problems was solved. :)
     
  13. shaunp macrumors 65816

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    #13
    Sorry missed that. Have fun. :)
     
  14. Fishrrman macrumors G5

    Fishrrman

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    Feb 20, 2009
    #14
    shaunp asks:
    "What will a 3rd partition give you? I honestly can't understand why you would need to do this."

    Perhaps the OP has a need for it, even if you can't understand why.

    My Mac Mini internal drive (1tb HDD) has FIVE partitions:
    - Boot backup (I boot and run from an EXTERNALLY-mounted SSD)
    - Main backup (clone of my main data partition - also on external SSD)
    - Music -- all music files stored here
    - Media -- photos and saved videos stored here
    - General -- backups of installers, apps, etc.

    Normally have at least 7 or 8 drive icons on my desktop at all times.
    All backed up on other drives elsewhere.

    No problems whatsoever keeping track of what belongs where...
     
  15. rich1812 thread starter macrumors member

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    #15



    i always chuckle seeing people question the motive of the poster's technical question. A computer is a highly cusomizable machine that each user has his own requirement to meet his own personal needs. These people won't ask the original question but jump the gun to tell the user what and what not they need. How laughable!
     

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