A Fusion Drive Question

Discussion in 'iMac' started by GovtLawyer, Jan 1, 2014.

  1. GovtLawyer macrumors 6502

    Sep 6, 2008
    Is the 1TB fusion drive two physically separate drives - one a 128GB and the other comprising the remaining storage to 1TB? Or, is it a 1TB drive and a separate 128 SSD? Or, one physical drive equaling 1TB, with two different properties?

    If it is one drive, does it appear in finder as two different volumes? Also, if they are one drive, doesn't the SSD portion stand to fail if the HD fails?
  2. DeltaMac macrumors G3


    Jul 30, 2003
    The fusion drive has two physical parts. A relatively small SSD, and a much larger spinning hard drive. They are joined into one volume through a software technique called "core storage"- and only one volume appears to the system.

    Concise article about Fusion drive: http://www.techradar.com/us/news/co...t-it-is-and-how-it-speeds-up-your-mac-1154051

    I think a quick answer to your question about losing one of the physical drives:
    The core storage is two devices, combined by software into one volume. If one device fails, then the volume is done, too. It's more important than ever that you have a good backup plan, just to avoid that kind of disaster.
  3. GovtLawyer thread starter macrumors 6502

    Sep 6, 2008
    Graet Answer

    Thanks for the answer. The linked page is very instructive. I now have the understanding of the drive I had hoped to.

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