Copying multiple files/folders = fragmentation?

Discussion in 'macOS' started by discofuel, May 12, 2011.

  1. discofuel macrumors 6502

    Joined:
    Feb 21, 2010
    #1
    Does copying multiple items individually fragment the disk or is mac os x cleverer than that?

    For example if I start copying a large folder to an external disk, and then while it's copying, I start copying another large folder, does this fragment the drive or has mac os already reserved the portion of the drive?

    So I guess my question comes down to if it's better to wait until a folder has copied to a drive before copying the next one?
     
  2. MisterMe macrumors G4

    MisterMe

    Joined:
    Jul 17, 2002
    Location:
    USA
    #2
    Fragmentation on a Mac is simply not the concern that it is in Windows--particularly the DOS-based Windows that used FAT32. Even though Microsoft has not used FAT32 as its main file system for a decade, the memories of FAT32 are still strong. The Mac has always been much more robust in handling fragmented files. MacOS X automatically defragments all but huge files. Copying files to drive with a lot of free capacity is a cheap defragmentation strategy. This means that your copies on the destination drive will be less fragmented than those on the source drive.
     
  3. niksimpsons macrumors member

    niksimpsons

    Joined:
    May 12, 2011
    #3
    No, Mac OS X can handle fragmentation of up to 20 MB files. For larger than this size third party tool is only solution. Any space left over between the last byte of the file and the first byte of the next cluster is a form of internal fragmentation. In this particular case since two files are copying simultaneously so data become fragmented that means data will not save in contiguous memory locations. Os will save data anywhere in hard drive taken from either of the files. And hence data get fragmented and no free space would be created between the data. As result OS will take more time in accessing the data later on.
     
  4. MisterMe macrumors G4

    MisterMe

    Joined:
    Jul 17, 2002
    Location:
    USA
    #4
    We know what fragmentation is. This is not the point. Fragmentation is the most efficient strategy for storing data on a hard drive. The problem with fragmentation is not so much with fragmentation, but the computer's file system. A fragmented files system does not imply a slow file system. Windows users associate the two, primarily because they are used to the behavior of FAT32. This Mac user has used and managed Macs for 22 years. I have benchmarked these computers before and after defragmentation. Defragmenting a Mac results in a performance increase of at most 5% in my experience. This is a figure that is indistinguishable from random fluctuation.

    As a Mac user almost exclusively until my firm issued my secretary a Windows PC, I wondered why Windows users put so much effort into defragging. After running the built-in defrag routine on the secretary's PC, I was astounded. It improved the computer's performance by an order of magnitude. Within a week or so, the performance of the Windows PC degraded as its hard drive again fragmented.

    The takeaway message:

    Mac, HFS/HFS+, defragging is a waste of time. In MacOS X, Apple explicitly states that it can do more harm than good.

    Windows, FAT32, Defragging is essential.

    Windows, NTFS, I have not conducted benchmarks. However, my seat-of-the-pants assessment is that fragmentation with this file system is not nearly the problem that it is with FAT32.
     
  5. niksimpsons macrumors member

    niksimpsons

    Joined:
    May 12, 2011
    #5
    I completely agree with your point that importance or need of defragmentation is much high in wndow as compared to Mac.. According to Apple (http://support.apple.com/kb/HT1375?viewlocale=en_US), defragmentation via third party tool may help if:
    1. Disks are almost full
    2. Often modify or create large files (such as editing video)
     

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