Macintosh HD is a logical volume - is this okay?

Discussion in 'Mac Basics and Help' started by bijtis, Jan 25, 2016.

  1. bijtis macrumors newbie

    bijtis

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    Jan 22, 2016
    #1
    Hey all,

    I'm fixing a MBP for a friend. Her HD couldn't be repaired and so I backed up what I could and erased it, but then ran into an issue whereby the machine wouldn't boot from USB (despite it being visible in Disk Utility).

    After trying a few different things, I opted to use the machine's internal HD as the install media. I burned the installer to it with createinstallmedia, and when I switched the machine on it booted into Utilities. I used Disk Utility to create a "Macintosh HD" partition for the installation, and after a nail-biting 30 minutes or so, I had a working system.

    I thought it'd be a good idea to remove the "Install OS X El Capitan" partition from the drive, but realised that it's a physical volume and so cannot be removed (is that correct?).

    I just wanted to ask, are there any pitfalls in running OS X from a logical volume? I've rebooted the machine with no issues. Just want to check that it'll all be cool before I return it to my pal.

    Thanks in advance!
     
  2. Weaselboy Moderator

    Weaselboy

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    #2
    If you install El Capitan on a newer Mac portable that has a CPU that supports AES-NI and there is no Bootcamp (Windows) partition present, the install will convert the installed volume to a core storage volume. This is normal and not a problem. This would have happened even if you had not installed from the hard drive.

    Were you also wanting to now delete the installer volume?
     
  3. bijtis thread starter macrumors newbie

    bijtis

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    Jan 22, 2016
    #3
    I would like to, yes, otherwise it's just wasted space. Is that possible? Erase is grayed out on Disk Utility.
     
  4. Weaselboy Moderator

    Weaselboy

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    #4
    Open Disk Utility and select the physical drive itself (like the WD in my screenshot). Is the installer partition on the top and Macintosh HD on the bottom? I suspect it will be.

    Screen Shot 2016-01-25 at 2.14.47 PM.png

    Here is the problem if Macintosh HD is on the bottom. Using Disk Utility you can resize partitions (volumes) but using my example, you cannot resize Other up even if your remove Backup. You could, in my example, remove Other and resize Backup down to fill the drive.

    So if your drive is like I think it is, you will need to clone off Macintosh HD to an external drive, then erase the entire internal drive to one partition, then boot to the external and clone it back. You can use the 30 day trial of Carbon Copy Cloner to do this.
     
  5. bijtis, Jan 25, 2016
    Last edited: Jan 25, 2016

    bijtis thread starter macrumors newbie

    bijtis

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    Jan 22, 2016
    #5
    In that case, good news! Macintosh HD is up top. I can resize it as I please, it's the installer partition that won't budge. But I can't remove it either.

    (I said before that the "Erase" button is grayed out when the installer partition is selected in disk utility. I misspoke; what I meant was that the "-" button beneath the pie chart in the disk's Partition menu is grayed out.)
     
  6. Weaselboy Moderator

    Weaselboy

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    #6
    Woot! Okay... let's try this.

    Restart then hold command-r at boot to get boot to the recovery partition. Once there launch Disk Utility and try to remove the installer volume.

    Then we need to convert the Macintosh HD volume so it is not a core storage volume any longer and can be resized. To do that (while still in recovery), click the Utilities menu up top then launch Terminal an enter the command below exactly like I have it and wait for it to finish reverting the core storage.

    Code:
    diskutil cs revert /
    Then you should be able to resize Macintosh HD into the space freed up by dumping the installer partition.

    Edit: As I think about this, I think we may still have the other issue I described. I believe when core storage is on it make that volume appear up top even though it is not. Run the revert command first then see what it looks like in Disk Util.
     
  7. bijtis thread starter macrumors newbie

    bijtis

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    Jan 22, 2016
    #7
    Alright - I'm in the middle of transferring all the backed-up data so it'll be about an hour before I can try this!
     
  8. Weaselboy Moderator

    Weaselboy

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    #8
    Just to clarify, if you can revert and remove the bottom installer volume, then resize, that is all non-destructive, so no need to move off the data. But if that does not work, you will need to move the data off and go back to my initial suggestion of a file wipe of the drive and copy back.

    That said, it is a good idea to clone off anyway in case things go badly. :)
     
  9. bijtis thread starter macrumors newbie

    bijtis

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    Jan 22, 2016
    #9
    Wait, am I reverting the installer volume that I want rid of or the Macintosh HD volume that I want to keep?
    --- Post Merged, Jan 25, 2016 ---
    Sorry, I've seen your amended post now.
     
  10. Weaselboy Moderator

    Weaselboy

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    #10
    You will be reverting the Macintosh HD core storage volume so it can then be resized after the installer volume is gone.
     
  11. bijtis thread starter macrumors newbie

    bijtis

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    Jan 22, 2016
    #11
    Code:
    / is not a CoreStorage Logical Volume
    Disk Utility in recovery mode lists the mount point of Macintosh HD as "/Volumes/Macintosh HD" and the installer volume as "/Volumes/Install OS X El Capitan". Don't I need to target one of those with the command?
     
  12. Weaselboy Moderator

    Weaselboy

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    #12
    Yes I'm sorry. That / alone will work when booted to the volume, but you are correct you need to target Macintosh HD when in recovery.
     
  13. bijtis, Jan 25, 2016
    Last edited: Jan 25, 2016

    bijtis thread starter macrumors newbie

    bijtis

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    Jan 22, 2016
    #13
    That worked, but as you predicted the Install volume has moved to the top. Once again, I seem to be able to resize Macintosh HD as before, but I cannot remove the Install volume.

    EDIT: Does this mean that when I reboot, it will attempt to boot from the (now empty) installer volume?

    EDIT: Yes it does. Is there some way to reverse the process and make Macintosh HD a CoreStorage volume once again? I can live without the 6GB or so that the installer is taking up.
     
  14. Weaselboy Moderator

    Weaselboy

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    #14
    I was afraid of this. The only way then is to move data off to another disk and reformat then move it back.

    No harm in just leaving it like you said. You don't really need to convert to back to core storage if you don't want, but if you do, use the exact same command except convert instead of revert.

    You should be able to option key boot to Macintosh HD then go to System prefs and in the Startup Disk pane select it as the boot drive.
     
  15. bijtis thread starter macrumors newbie

    bijtis

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    Jan 22, 2016
    #15
    Just to tie off this loose end - I just set the Macintosh HD volume as the startup disk and left it as is. So there's an empty 12gb partition labelled "Install Mac OS X El Capitan" which I'm sure will confuse someone in the future.

    Thanks for your help Weaselboy!
     
  16. DeltaMac macrumors 604

    DeltaMac

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    #16
    You could always just rename that Install... partition.
    "Empty space" would be kool, eh?
     

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