SSD and Defragmentation

Discussion in 'macOS' started by vmachiel, Aug 24, 2011.

  1. vmachiel macrumors 68000

    Joined:
    Feb 15, 2011
    Location:
    Holland
    #1
    Hi,

    So i read somewhere that Mac OS X automatically defragments your hard drive. I also read that SSD's don't need to be defragmented and that it can actually reduce it's life span. Now that i've manually installed a SSD, will OS X still defragment it? And if so, can you disable this?

    Thank you!
     
  2. ScoobyMcDoo macrumors 65816

    Joined:
    Nov 26, 2007
    Location:
    Austin, TX
    #2
    As best I can tell there is no "background automatic defragmentation" that OSX does as some folks have suggested. Instead they use techniques in writing data to avoid fragmentation in the first place. If you read Apple's articles on the subject, you will find they never mention defragmentation - they use the term optimization.
     
  3. vmachiel thread starter macrumors 68000

    Joined:
    Feb 15, 2011
    Location:
    Holland
  4. ICEBreaker macrumors 6502

    Joined:
    Aug 12, 2007
    #4
    According to Amit Singh's article Fragmentation in HFS Plus Volumes, which mind you was written in 2004 in the days of Panther, Mac OS employs a two-pronged approach of On-The-Fly Defragmentation and Hot File Clustering to reduce the level of fragmentation. I don't know about the OTF defragmentation, but Mac OS X does utilise hot file adaptive clustering. Read more About disk optimization with Mac OS X.
     
  5. Quad5Ny, Aug 24, 2011
    Last edited: Aug 24, 2011

    Quad5Ny macrumors 6502a

    Quad5Ny

    Joined:
    Sep 13, 2009
    Location:
    New York, USA
    #5
    In addition to the hot band, OS X will try to defragment a file when opening it if all these conditions are met:
    OS X does not do full disk defragmentation like Windows. I doubt this would have any large effect on SSD life.

    I would be more concerned about page-outs (if your low on RAM) and the sleep (hibernation) file. And even then, your SSD will probably outlast your computer.
     

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