SSD + 1TB and fusion?

Discussion in 'Mac mini' started by Magrathea, May 11, 2013.

  1. Magrathea macrumors regular

    Joined:
    Aug 21, 2008
    #1
    So I discovered that as of 10.8.3 OSX will make a fusion drive automatically if you add an SSD as the primary and use the drive that come with the mini as a secondry drive (care of OWCs kit) Both drives were formatted before hand.

    This sucks as if you have a 250GB ssd you want the full speed of it not combine the two. We discovered this and fixed the problem by temporary unplugging the 2nd hard drive and just leave the primary, the ssd plugged in. WE did an install from the internet and all is now fine.

    So the questions now is that if we go and plug back in the 2nd hard drive, the one that came with the mini, will the Mini on boot try to make a fusion drive out of it and mess out install up??


    BTW the OWC instructions regarding this are not very good
     
  2. philipma1957 macrumors 603

    philipma1957

    Joined:
    Apr 13, 2010
    Location:
    Howell, New Jersey
    #2
    un plug the ssd and format the oem drive as a booter. plug in the ssd you will have 2 booters. you can pick either one to boot.
     
  3. Fishrrman macrumors G3

    Joined:
    Feb 20, 2009
    #3
    I believe you will only get "forced fusion" if you try to run Disk Utility while booting from the recovery partition.

    So… the solution (IF you want an SSD and an HDD inside the Mini withOUT fusion) is to NEVER RUN DISK UTILITY while booted from the recovery partition -- at least until Apple fixes this in a future software upgrade (whether they will or not is unknown at this time).

    Of course there are still situations where you would want to run DU while "booted externally" (from a drive other than your primary boot drive).

    For this reason, like Philip suggests above, I would recommend the following:
    1. Partition the 1tb HDD internal drive into at least two partitions.
    2. The first partition should be 250gb (or less, if you wish). The other can be the remaining space.
    3. Use CarbonCopyCloner or SuperDuper to clone your SDD to the first partition on the HDD.

    This should do two useful things:
    1. You will now have an "alternative boot source" that is immediately available if you need it (and with a clone, an exact copy of all your system, apps, user accounts, etc.)
    2. You don't have to worry about DU "force fusing" your SSD any more.
     
  4. philipma1957 macrumors 603

    philipma1957

    Joined:
    Apr 13, 2010
    Location:
    Howell, New Jersey
    #4
    Nice improvement on my idea.
     
  5. benwiggy macrumors 68020

    Joined:
    Jun 15, 2012
    #5
    You will get the "full speed" of the SSD for data that is on the SSD portion of the the fused volume.

    If you have less than 246Gb on the volume, all of it will be on the SSD.

    If you have more than that amount, then the files (correction, the blocks of data) that you use the least will be moved onto the HDD; the data blocks of files that you use the most frequently will be on the SDD.

    Data on the SSD will still move at the speed of the SSD.
     
  6. Magrathea thread starter macrumors regular

    Joined:
    Aug 21, 2008
    #6
    Ok, thanks for the suggestions guy but regarding my specific question: If I plug in the 2nd drive, it is now installed but the cable is unplugged, will the system boot normally. The system is fully up and running, OSX is installed on the SSD and the guy is using his machine.

    Thanks
     
  7. gnasher729 macrumors P6

    gnasher729

    Joined:
    Nov 25, 2005
    #7
    And you successfully managed to avoid using one of the biggest enhancements of MacOS X 10.8. Congratulations. (If you think that sounds sarcastic, that's intentional).
     
  8. philipma1957 macrumors 603

    philipma1957

    Joined:
    Apr 13, 2010
    Location:
    Howell, New Jersey
    #8
    maybe. since I do not know the state of format that you left the oem drive in. if you gave it a title and a mac format you should be good. if you did not you won't be good.. so I will ask you how did you name the oem hdd and how did you format it. BTW if you left it alone with the boot info that it came with and if you named the ssd anything but the same name as the oem hdd you could plug in the oem hdd now and be fine.

    if they now are both named Macintosh HD you will need to play with the oem hdd. just rename it.
     

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