Did I erase part of my fusion drive?

Discussion in 'iMac' started by BlueMoonForever, Jun 8, 2013.

  1. BlueMoonForever macrumors 6502

    Sep 2, 2012
    So yesterday I attempted to install Windows 7 HP since I got a cheap plug in CD-Rom drive from Best Buy. Long story short, Windows wouldn't install on the partition Mac OS X made. I kept getting some GPT error I believe. I tired to format it, like I did on my 2010 MBP, but nothing worked. Due to my stupidity, I actually formatted the Mac (160GB) partition. My mac wouldn't boot obviously. I got into disk utility and then somehow managed to combine 900GB+160GB (which I'm assuming was the SSD portion of the hard drive).

    I restored everything from Time Machine, but now my hard drive capacity is like 1.11TB in size, whereas before it was only 968GB. Did I screw up my fusion drive? This iMac is fully covered under warranty?

    For what its worth, the apps boot up exactly like before. I did understand the fusion concept as the OS and apps install on the fusion drive, whereas everything else goes to the larger drive.
  2. joe-h2o macrumors 6502a

    Jun 24, 2012
    You actually don't fully understand the fusion concept - it's not just the OS and apps that go onto the SSD.

    When the amount of data you have is less than the size of the SSD, it will *all* be kept on the SSD - OS, apps, data, everything. If you never ever go above that size of the SSD (which is about 100 GB worth for the fusion drive, since the Mac reserves a portion of the 128 GB SSD for its own use), then you'll never even touch the hard drive at all.

    When you have more data than the size of the SSD, that's when it starts spilling over. The OS will decide what data you use most frequently and it will attempt to keep that on the SSD. Files you very rarely touch will be kept on the HDD. If you start using some of the files on the HDD more frequently, it will move those up to the SSD and move some lesser-accessed files back down to the HDD in exchange.
  3. BlueMoonForever thread starter macrumors 6502

    Sep 2, 2012
    Thank you!!! You really cleared it up for me. Any clue why I couldn't get Windows to load? Wouldn't let me partition the bootcamp drive to NFTS.
  4. chrfr macrumors 604

    Jul 11, 2009
    Are you using the Boot Camp Utility to set up your Windows partition? You do not want to be doing any partitioning of a Fusion Drive from within Windows.
  5. MeatRocket macrumors regular

    Jun 9, 2013
    In the Sandbox
    It sounds to me like after you did the BootCamp Assistant and rebooted to install Windows, you didn't go to the advanced settings in the Windows disk portion of setup and format the partition. BootCamp will create the partition, but Windows still has to format it.

    Here is a good video on the whole process. The part I'm talking about is at 5:30


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