delete CoreStorage Volume completely

Discussion in 'OS X Yosemite (10.10)' started by MikB, Nov 16, 2014.

  1. MikB, Nov 16, 2014
    Last edited: Nov 16, 2014

    MikB macrumors newbie

    Joined:
    Jan 18, 2013
    #1
    I installed Yosemite on an external 3TB drive. I made a specific 300GB partition on it to hold the system and a second for data. Installation worked fine. However, according to Disk Utility in both Mavericks and Yosemite there is only a little more than 800GB available on the whole disk.

    When I run
    Code:
    diskutil list; echo; diskutil cs list
    it says there are no CoreStorage Volumes, but I knew from the Yosemite installation that there is one.

    How can I get rid of the CoreStorage Volume even as OS X won't acknowledge there is one? Do I dare to delete and erase the complete drive from Disk Utility in Mavericks? It seems risky as it can't even show me the lost partition space.

    Here's the output from the command above:

    Code:
    /dev/disk2
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:      GUID_partition_scheme                        *801.6 GB   disk2
       1:                        EFI EFI                     209.7 MB   disk2s1
       2:                  Apple_HFS X Drive                 320.1 GB   disk2s2
       3:                 Apple_Boot Recovery HD             650.0 MB   disk2s3
    
    No CoreStorage logical volume groups found
     
  2. MikB thread starter macrumors newbie

    Joined:
    Jan 18, 2013
    #2
    Thanks, but I don't need to recover any files. I want to recover about 2.2 TB of drive space that OS X ignores.
     
  3. MikB, Nov 16, 2014
    Last edited: Nov 16, 2014

    MikB thread starter macrumors newbie

    Joined:
    Jan 18, 2013
    #3
    Update

    I ran
    Code:
    cat /dev/random > /dev/disk2
    as su and all partitions are gone now.

    At first, the available disk space was still only 801GB. After a while it showed up properly in Disk Utility as 3.0TB though. Excellent!

    Thanks to Topher Kessler for posting the proper commands in How to fix deep formatting problems with OS X drives!

    CoreStorage is great technology. Apple info still leaves a lot to be desired.
     

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