Can a >2.2 TB internal bootable hard drive be used in an iMac?

Discussion in 'Windows, Linux & Others on the Mac' started by princealfie, Aug 31, 2012.

  1. princealfie macrumors 68030

    princealfie

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    #1
    I just installed a 4 TB hard drive into my 2006 iMac but I can't seem to figure out how to make it identify all 4 TB. It only does the 2.2 TB partition since it is MBR instead of GUID (UEFI) for the bootable drive. Any ideas what to do with all that extra space on my drive?
     
  2. Intell macrumors P6

    Intell

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    #2
    Repartition it as a GUID drive. That will give you the full drive space.
     
  3. princealfie thread starter macrumors 68030

    princealfie

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    #3
    How do I repartition it?
     
  4. Intell macrumors P6

    Intell

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    #4
    Startup from your Mac OS X reinstallation disc, go to the Utilities menu, select Disk Utility, click on your drive, go the partition tab, change the volume scheme to 1 (or as many as you want), click options, change it to GUID, click apply. Note: This will erase all data on the hard drive.
     
  5. princealfie thread starter macrumors 68030

    princealfie

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    #5
    Thanks so basically will it allow me to use Windows 7 only and erase the Mac OS X portion or do I have to install Mac OS X along with Windows?
     
  6. murphychris macrumors 6502a

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    #6
    You shouldn't use a disk larger then 2.2TB with Windows using BIOS hardware. And on Apple hardware, it is effectively BIOS hardware as a result of the EFI CSM (Compatiblity Support Module) which Apple provides for supporting Windows.

    BIOS booting Windows requires the boot disk use MBR partitioning scheme.

    MBR has, in effect, a 2TB limit for the disk.

    There are some attempts to get around this through partitioning, but none of the partition tools I've used on Mac OS or Linux will let you do this. They refuse to partition such disks using MBR scheme. Instead, you have to hand code your own partition scheme.

    The way around this is UEFI booting Windows, instead of relying on the CSM. There are other threads discussing how to do this, with varying degrees of success. UEFI booting Windows requires the boot disk use GPT partitioning scheme.
     
  7. princealfie thread starter macrumors 68030

    princealfie

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    #7
    I will try the GUID method and do the dual boot but if doesn't work I guess that I'm in serious trouble here.
     
  8. princealfie thread starter macrumors 68030

    princealfie

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    #8
    Installing Mac OS X right now and looking good so far. Then I can install Win7 with a huge partition for my artwork and games!
     
  9. princealfie thread starter macrumors 68030

    princealfie

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    #9
    Didn't work so ended up just setting my iMac to Mac OS X strictly. Kind of disappointing but maybe the newer iMacs can support it?
     
  10. Intell macrumors P6

    Intell

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    #10
    The 2.2TB is a limit of the MBR partition scheme. It exists for all Macs running Boot Camp.
     
  11. iMacDragon macrumors 65816

    iMacDragon

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    #11
    If you partition the drive manually before installing both OS's to put the windows partition within the first 2TB, and the OS X one after it, it should work. Though, it might need hacking to get the MBR right as disk utility will probably not create a hybrid mbr for the drive.
     
  12. murphychris macrumors 6502a

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    #12
    Disk Utility definitely will not let you use MBR, nor create a hybrid MBR for a GPT disk, if the disk is larger than 2.2TB. And the command line utility fdisk for creating/editing MBRs will not work either. Nor will the Linux fdisk command.

    It simply isn't recommended.

    gdisk will create a hybrid MBR on a > 2.2TB disk that could work in certain circumstances, i.e. the starting sector LBA cannot be beyond the 2.2 TB limit, and the partition size for any partition cannot be bigger than the 2.2 TB limit. If Windows is to be in the last MBR partition entry (#4) then it would have to be 2.2TB in size, or waste the remaining disk space. If Windows were in the 2nd or 3rd position it could be a smaller size, but then it gets trickier how to protect and/or share the Mac OS partitions.

    In any case it is so fragile and non-standard that you couldn't reliably allow anything to ever make disk partition modifications, or even understand the resulting partitions.
     

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