Resize Primary Drive

Discussion in 'macOS' started by leafsrule99, Oct 27, 2010.

  1. leafsrule99 macrumors newbie

    Joined:
    Jan 1, 2010
    #1
    Hi Guys
    So i have 2 partitions:
    1) Primary Partition: is GUID Partition table which is the start up disk
    Actual Size: 120 gb Free Space: 6gb
    2) Second Partition: is GUID partition table which is for personal files
    Actual Size: 200gb Free Space: 100gb

    If i want to make the primary partition 150gb (increase size by 30gb) and second parition 170gb (reduce size by 30gb)

    How do i use the disk utility to do that.

    I tried to move the dividers but it only worked for the second partition not the first.

    Thanks in advance
     
  2. spinnerlys Guest

    spinnerlys

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    #2
    As you can see from the following image, partition 2 immediately starts where partition one ends, and if partition 2 has already half of its size taken by data, chances of that data being spread all over the partition 2 are quite normal, but the image shows the 100GB of data as one continuous block (for simplification). As that data on partition 2 is written onto the platter (the 320GB HDD will have two platters, each 160GB, but the same principle applies) right after partition 1 ends, one can not expand partition 1 any further, as with current mainstream file systems, partitions need to be continuous.
    [​IMG]

    To resize your partitions, you need to copy the data off the internal HDD onto an external HDD, using CarbonCopyCloner or SuperDuper to clone the Mac OS X partition, formatting the internal HDD to your liking and partition it again, while booted of the cloned Mac OS X system on the external HDD or using Disk Utility.

    Guide on how to use Disk Utility from the restore / installation DVD.
    Format Your Hard Drive Using Disk Utility
    Partition Your Hard Drive With Disk Utility
     
  3. richard.mac macrumors 603

    richard.mac

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    #3
    since Leopard Disk Utility has allowed you to non destructively resize and add partitions.

    to edit partitions on your boot disk you need to boot into your installer DVD and choose Disk Utility from the Utilities menu.
     
  4. spinnerlys Guest

    spinnerlys

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    #4
    Does that mean, my post above is false? :confused:
    How can one resize partition 1, if partition 2 is starting right after partition 1 and if partition 2 has data on it, that s most likely written in the blocks right after partition 1 ends?

    Because I once tried to repartition my Macintosh HD using the Restore DVD and Disk Utility (with Mac OS X 10.6) and it didn't work, as data was scattered across the platters.
     
  5. maflynn Moderator

    maflynn

    Staff Member

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    Boston
    #5
    Just like boot camp, if the data is fairly well scattered, then you cannot adjust the partition size, if however its compacted you can. I've done this a number of times successfully.

    As with any modifications regarding your drive, you need to be sure you have a backup.

    edit:
    One simple request, also can you use the timg tag instead of the img tag. That is one huge image and it really impacts my reading/loading this thread.
     
  6. spinnerlys Guest

    spinnerlys

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    #6
    That's what I was getting at with my first reply and why I got confused by richthomas' post.

    Done. Just out of curiosity, is the image too wide or is it too big in its file size for you?
     
  7. maflynn Moderator

    maflynn

    Staff Member

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    #7
    Yes to both, it was way too wide, but pulling up this thread took a while (I'm on dsl) as the image was being downloaded. Of course once loaded and cached the second problem was mitigated.
     
  8. richard.mac macrumors 603

    richard.mac

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    #8
    oh ok sorry, just got a bit confused. looks as tho you can only decrease the size of partition 1 (by 6 GB), which would allow partition 2 to increase by 6 GB.
     
  9. leafsrule99 thread starter macrumors newbie

    Joined:
    Jan 1, 2010
    #9
    so basically it means...its not really possible to do so easily
     
  10. spinnerlys Guest

    spinnerlys

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    #10
    Yep. You have to copy/clone your data onto an external HDD and partition the internal HDD to your liking and copy/clone the data back.
    As the blocks used for partition 2 are immediately beginning after the blocks of partition 1, and the blocks for partition 2 have already been used, partition 1 can't be expanded.
     

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