Create a new partition

Discussion in 'OS X Yosemite (10.10)' started by Mais78, Dec 11, 2014.

  1. Mais78 macrumors regular

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    #1
    I am trying to create a new partition on an external hard drive but it says I can only split the current (and only) partition in two? Why I cannot choose the size of the new partition?
    Thanks
     
  2. Weaselboy Moderator

    Weaselboy

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    #2
    You need to first shrink the existing partition, then you can add a second one at the end. This should help you out.
     
  3. simonsi macrumors 601

    simonsi

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    #3
    Sounds like your existing partition is taking up all the space and you are selecting "2 partitions" from the drop-down?

    Instead, drag the resize slider on the existing partition (bottom right corner of the partition space box), move it up as required to shrink it, then select "+" from the bottom of the partition area, that will give you a new partition filling the vacant space. Hit "Apply" when you are happy.
     
  4. Mais78 thread starter macrumors regular

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    #4
    Not really, the first partition is taking 30pct of the drive, i can create a second one but i cannot choose the size, it says has to be same size. Once the second one is added i cannot change the size of the new partition, no slider there. Any clue?

    ----------

    Ps i m on yosemite if that makes any difference
     
  5. simonsi macrumors 601

    simonsi

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    #5
    Can you post a screenshot? The "slider" is the shaded corner of the partition box.
     
  6. Mais78 thread starter macrumors regular

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    #6
    Here we go. Thanks
     

    Attached Files:

  7. simonsi macrumors 601

    simonsi

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    #7
    Ah - I have comp,ained to Apple about this, when you installed Yosemite it converted the entire drive and any partitions on it to Core Storage - and Core Storage cannot have its partitions managed or changed in any way by Disk Utility - catch-22.

    Unless you have Filevault turned on you may be able to revert them to normal partitions and have them managed by Disk Utility, refer to this thread for the commands:

    Revert Core Storage
     
  8. Mais78 thread starter macrumors regular

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    #8
    Thanks, mine is a mac mini 2014 that came with Yosemite already installed. Is it the way it is supposed to be?
     
  9. simonsi macrumors 601

    simonsi

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    #9
    That is how Apple ship, that is how Yosemite installs. Ending up with partitions that Apple's own supplied Disk Utility can't manage seems somewhere between odd and bizarre.

    As that was an original ship with Yosemite, you may not be able to revert the CS volumes to standard, I've no experience there. Do you have access to a Genius Bar or Apple Store?
     
  10. Mais78 thread starter macrumors regular

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    #10
    This means i cannot create partitions at will on any external drive because i m running yosemite?

    I can call Apple i guess
     
  11. simonsi macrumors 601

    simonsi

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    #11
    No, only that internal drive.

    Run the commands in that thread I gave you, if it can be reverted it will tall you, then you can revert and all good.

    If you can't then you will have to backup, format, install Yosemite, then revert, then create/resize partitions as normal.
     
  12. Weaselboy Moderator

    Weaselboy

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    #12
    Nah... we can get you fixed up.

    Yosemite should not have converted the externals to core storage. I think you may have encrypted your external drive (perhaps checked the encryption box in Time Machine?).

    Run this command in Terminal and post up the results and we can figure out what is going on.

    Code:
    diskutil cs list
     
  13. simonsi macrumors 601

    simonsi

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    #13
    Ooops - gave a wrong steer on the external, hope you can fix him up, I've gotta run...
     
  14. Mais78 thread starter macrumors regular

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    #14
    Correct, the external drive is encrypted. I never used Time Machine, the purpose to create the partition was right that, assign it to TM.
     
  15. Weaselboy Moderator

    Weaselboy

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    #15
    Okay... that's your problem. You cannot resize encrypted volumes. Go to Disk Util and select the partition then in the File menu select Turn off encryption. Once that is done you should be able to manipulate normally. Then you can reencrypt if you want.
     
  16. Mais78 thread starter macrumors regular

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  17. Weaselboy Moderator

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    #17
    Yep... that's what it is. Just UNencrypt and you can do what you wanted.
     
  18. Mais78 thread starter macrumors regular

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    #18
    ehmm....how do you do that?
    Thanks!
     
  19. Weaselboy Moderator

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    #19
    Just follow this should fix you up.
     
  20. Mais78 thread starter macrumors regular

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    #20

    Have done it from the finder in the meanwhile. Now in the file menu of disk utility turn off encryption is greyed out, so I think I made it.

    Still I cannot change size
     
  21. simonsi macrumors 601

    simonsi

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    #21
    In the screenshot it said it was a logical volume, now it is unencrypted you may still need to convert it to normal storage, re-run the list command, does it state it is revertible now?
     
  22. Mais78 thread starter macrumors regular

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    #22
    I am messing everything up... In the end I just reformatted the whole externale drive to Mac Journaled non-encrypted. Once I did that I could create the two partions, so far so good.

    I then encrypted the two partions separately, once I did that the two partions in the disk utility now appear as two different drives, each with one indented partion.

    Tryed to decrypt but it does not go back to previous state and I cannot delete any of the two partitions (nor I can reformat).
     
  23. Weaselboy Moderator

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    #23
    That is normal if you have encrypted them both again.

    So how are things now?
     
  24. Mais78 thread starter macrumors regular

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    #24
    I managed to create the two partitions. But I would like also to understand how to go back to one drive with two unencrypted partitions indented underneath (I will need this in the future to resize one of the partition). My attempts to un-encrypt were unsuccessfull, click on turn off encrymption but nothing happens. Even though I noted that in one instance, after an apparent unsuccessful attempt to unencrypt, after rebooting the whole computer the partition showed up as unencrypted, but only one.
    Is the encryption from the finder different from the encryption from the Disk Utility?

    Sorry to waste your time, this is my first mac and trying to get to know it. thanks

    PS Is there any performance enhancement if I reformat the drive as safe erase vs fast erase? Does the fast erase leave old data scattered in the disk?
     
  25. Weaselboy Moderator

    Weaselboy

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    #25
    If you made the two partitions the size you want them then after that encrypted them both, and they both have those duplicate names with the indent that is normal. That is because when you encrypt it shows the "real" volume name then the "logical" volume below that. So that part is okay.

    You unencrypt just like I mentioned in Disk Utility. It does not show any indicator as it unencrypts, so I think you jumped the gun there when you rebooted. If you enter the command "diskutil cs list" in Terminal it will show unencryption progress and if it is done.

    For example, that command would show this while the drive is being encrypted. Note the size total and converted to see how much is done.

    Code:
    Encryption Status:           Unlocked
        Encryption Type:         AES-XTS
        Conversion Status:       Converting
        Conversion Direction:    forward
        Has Encrypted Extents:   Yes
        Fully Secure:            No
        Passphrase Required:     Yes
     Disk:                       disk6
        Status:                  Online
        Size (Total):            569869340672 B (569.9 GB)
        Size (Converted):        231454277632 B (231.5 GB)
        Revertible:              Yes (unlock and decryption required)
        LV Name:                 Heap
        Volume Name:             Heap
        Content Hint:            Apple_HFS

    So if you want to change this again just unencrypt then adjust partitions then reencrypt.

    Doing it from Finder or DU use the exact same OS command internally and have the same end result.

    Secure erase is not intended to help performance. It is more for overwriting your data for security so nobody can restore your erased data. Like if you were selling your computer you would want to do this. No real reason to do it yourself routinely though.

    Not wasting my time at all. Glad to help. This is all very confusing stuff. :)
     

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