Big confusion here, Fusion drive

Discussion in 'macOS' started by becks87, Nov 28, 2012.

  1. becks87 macrumors newbie

    Nov 28, 2012
    hi guys,

    so i received my SSD yesterday and i installed my OS and some heavy applications on the SSD, and kept the HDD to store my music, downloads etc...

    but i was trying to organize my music library and it was giving me problems so i created a "fusion" drive....

    but i started thinking a lot about it.... should i keep the fusion drive or re separate my two drives and try the SSD and HDD configuration??

    please give me pros and cons!!!

    thank you in advance
  2. switon, Nov 29, 2012
    Last edited: Nov 29, 2012

    switon macrumors 6502a

    Sep 10, 2012
    RE: FUDs...


    I have no experience with Fusion Drives, yet ... but from what I read it sounds like that if you don't want to worry about what to put on the SSD portion versus the HDD portion of a FUD, then you should just keep the FUD. Since the FUD promotes/demotes in 128kB blocks and not entire files, you can gain significant speed from its operation without ever even having to think about it. On the other hand, if you are the sort that enjoys ultimate control, then separating your SSD and HDD allows you to specify precisely what is on the SSD versus the HDD. Obviously, this control comes with a time price, as you have to determine what files go where. And since the two drives, the SSD and HDD, will be separate partitions, when you transfer a file the whole file is copied from one partition to the other and thus you will have to remember to manually delete the transferred file from the initial drive. This also means that you will not gain efficiency from the fine granularity of the FUD mechanism (128kB versus entire files), but you will have better control over just which files are on the SSD.

    So, what type of person are you? Are you the type who wants the speed advantages of an SSD while keeping the colossal storage size of the HDD, all without requiring your intervention? Or are you the type who wants to micromanage your files and their placement on the SSD or HDD?

    Good luck,

    P.S. Just out of curiosity, why did problems with your music library cause you to create a FUD? Is it that your music library was too large to fit on the SSD?
  3. becks87 thread starter macrumors newbie

    Nov 28, 2012
    thank you switon,

    i decided to break up the Fusion Drive and micro managing stuff....
    i get more speed like so and maybe this will help my memory :D

    PS. what happened was that i wasnt able to restore all the rating and playlists.... managed from the FUD, but after much thought (and a good sleep :D) i decided to go with the two drives (SSD+HDD)

    my music library is only 40GB but the SSD is only 128GB so i want to use that space for more important stuff....
    all i have read suggests that the drive is more likely to fail.... and since i do a lot of downloading, photography etc. i dont wanna clog the SSD's 4GB cushion (for copying stuff)

    at least if one drive fails the other one will still be usable unlike the fusion drive (if one goes thats it for both)
  4. switon macrumors 6502a

    Sep 10, 2012
    RE: 4GB cushion...and...


    Yes, I believe you will find that the HDD is plenty fast for you iTunes Library, so there is no need to have it on the SSD.

    And about that "4GB cushion" --- I don't believe you can "clog" it, as the CoreStorage software will always clean out the SSD to leave 4GB free for future writes. Only if you transfer a file larger than 4GB will this "cushion" be used up and the remaining portion of the file (the portion > 4GB) will not initially write to the 4GB reserve on the SSD but rather will write directly to the HDD. But once that >4GB file is written, then CoreStorage will demote 4GB off of the SSD to the HDD, reestablishing a new 4GB of free space on the SSD for future writes.

  5. becks87 thread starter macrumors newbie

    Nov 28, 2012
    Thank u again switon

    i will just keep it separated for now.... will just buy a new mac in the future so the fusion thing will be built in :D

    you get what you pay for i guess :D

    have a good one

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