Re-partioning unused HD space question

Discussion in 'Mac Basics and Help' started by BingClawsby, Mar 30, 2011.

  1. BingClawsby macrumors regular

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    Mar 2, 2010
    #1
    I assume that when you get a new drive and want to partition it or totally reformat/partition an old one, that say, for example, you want to partion into 2 equal parts....that the drive will physically partition one from the mid point of the platter outwards, and the other inwards, correct?

    But now I want to take a hd thats already in use with files on it and now want to create a new partition out of the unused space created from deleting a whole bunch of files.

    Now we have a situation where the files I want kept are probably fragmented all over the drive.

    So my question is...when I go and create a new partition from the empty space I have, which will now give me a hd partitioned in 2, will those 2 partitions be spread out all over the place? Or will all the fragmented files kept that will now go onto one of the partitions be de-fragged together in one solid physical space on the hd?

    Thanks
     
  2. Tomorrow macrumors 604

    Tomorrow

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    #2
    You won't have the option to make a fragmented partition. Just defrag the drive first and you should be fine.
     
  3. BingClawsby thread starter macrumors regular

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    Mar 2, 2010
    #3
    Thanks

    Unfortunately I can't be at my machine now. Disk utility says I can create partitions on a drive with free space available. So if I go to do that whats it going to tell me? De-frag the drive first or something? Come to thing of it I have no idea if disk utility de-frags...never went there.
     
  4. Tomorrow macrumors 604

    Tomorrow

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    #4
    If you defrag first, there's a good chance that you'll increase the size of the partition you can create.

    Think of a bunch of books scattered all over some bookshelves; the largest individual space available (without moving any books) might be as large as the total empty space, or it might be much smaller. If you condense all the books together, eliminating empty spaces between them, then you'll have one very large contiguous space remaining.

    Partitioning a drive is similar to that; if you have 50 Gb free but a handful of files occupying parts of that space in or near the middle, you may only be able to make a 25 Gb (possibly smaller) partition; if you defrag first, virtually all of that 50 Gb will be available for a partition.

    I'm using made-up numbers, and that's a worst-case scenario, but that's the gist of it.
     
  5. BingClawsby thread starter macrumors regular

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    Mar 2, 2010
    #5
    Yes, yes, I know all that stuff :)

    Thanks

    I wanted to know what the sequence of events are? If the disk I want to put another partition on is fragmented, you're saying disk utility won't let me do it? If so, does disk utility de-frag? I don't know, I never got that far with any of DU's functionality.
    Or do I have to get a de-frag app? I know the OS does some de-frag in the background though, but probably not enough.

    Although, I could just move all the contents off the drive and reformat, but transferring about a tb of files back and forth will take a couple days.
     
  6. Tomorrow macrumors 604

    Tomorrow

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    #6
    The defragging going on in the background is individual files, not the entire drive.

    Links to more info and a free defrag utility here.
     
  7. BingClawsby thread starter macrumors regular

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    Mar 2, 2010
    #7
    Thanks! I'll try that iDefrag. Forgot about trying a demo as I just basically need to do this once
     

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