If you have a factory SSD/HDD and break the Fusion, disk utility won't format the resulting drives. You need to use the terminal or another disk tool (disk warrior, SoftRAID, etc).
If you have a factory SSD/HDD and break the Fusion, disk utility won't format the resulting drives. You need to use the terminal or another disk tool (disk warrior, SoftRAID, etc).
I attempted this on my new iMac and it won't allow it to reinstall the system unless you allow it to fuse the drives.
Let me say again this is a brand new 27" iMac.
Yes. I used both commands. I don't have any trouble with the terminal. It defused the drives, formatted them, and they showed up in the right side labeled both as Untitled. I restarted the computer, ran the installer, and it said during the installation process there were errors on the drive and do I want to fix it. It simply re-fused the drives and then the installer ran.
Target disk mode didn't work, and a USB thumb drive installer didn't work either. Target disk mode would allow me to install the OS from another computer, but the thumb drive would load up and say it doesn't work with my computer, likely because the computer requires a newer version of OS X to run. I'll most likely have to wait until I can make a USB booter that has the necessary drivers and such in the installer.
I attempted this on my new iMac and it won't allow it to reinstall the system unless you allow it to fuse the drives.
it can be done, other people have done it to the new iMacs and minis. If it is true then i will return my iMac when i get it.
I'd be glad to find some clever person's instructions on how if they can find a way to do it. Thumb drive of Mountain Lion straight from the App store won't install anything, Target disk mode produces a disk that won't boot, and using recovery mode (either off the disk or purely network) won't let you install unless you let it fuse the drives again.
Personally, I can deal with it until I can figure it out. I just don't want it fused because I'd rather use them as separate drives. It simply looks as if it would work if I had an installer other than the one made specifically for this computer that had everything necessary for this computer to work in it.
The MacWorld article also identifies this quirk:
http://www.macworld.com/article/2015664/how-to-split-up-a-fusion-drive.html
Fusion Drive quirks
If you split up a Fusion Drive you got from Apple, you won't be able to use Disk Utility to format the drives. Disk Utility will detect that the two drives used to be an Apple Fusion Drive and show them in red text.
Not to worry though, as you can install Mountain Lion without a problem. Just exit Terminal after you delete the CoreStorage setup, and choose to reinstall Mountain Lion from the list of choices in Recovery Mode. You can select which drive to install the OS on, and upon booting you'll have access to both your drives. You'll also be able to go into Disk Utility and format them once you've installed Mountain Lion, though if you boot from Recovery Mode you'll still get the same problem formatting them.
However, they only used the one command, and did not delete the Fusion drive from the disk table.
-howard
"I've already done that part. The OS X installer will not allow installing on the drives when they're split, only when they're fused. It comes up with a dialog saying there are errors in your drive do you want it to fix it and when you hit yes it fuses the drives then installs the OS."
The solution is to create a full clone of a "fresh" system (and apps) on an external drive.
Then, "un-fuse".
Then, "re-clone" from the cloned backup to end up with the same software you would otherwise have on a "fused" drive.
What you DO NOT want to do is to attempt a "fresh install" from the recovery partition AFTER un-fusing.
Apple has intentionally chosen to limit the user's options in Disk Utility when DU finds both an HDD and SDD installed. There should be a user option to either "repair" the two drives "as two individual drives" OR as a single, fused drive. Perhaps future versions of DU will address this. If not, perhaps the only usable repair utilities may be from 3rd-party sources.
I am getting a little worried, is anyone currently running a disjointed fusion drive set-up? I understand the recovery boot partition disk utility will balk at doing anything but re-constituing the fusion drive but what about the boot drive disk utility that will necessarily not be a special build.. (because install will have to be done from a separate drive cloned with a mountain lion install image)
to sum it up; is anyone running a disabled fusion drive and is it a good option at this point?
I've already done that part. The OS X installer will not allow installing on the drives when they're split, only when they're fused. It comes up with a dialog saying there are errors in your drive do you want it to fix it and when you hit yes it fuses the drives then installs the OS.
I also tried installing the OS from another computer via target disk mode, and the computer won't boot off the drive. There's something else in the computer practically forcing the fusing of the drives.
I have done this on my 2011 Mac Mini which already had the SSD partitioned for Windows and OS X as well as a hard disk data drive.
It is true as Apple has said that you can't create a SSD BootCamp partition on a fusion drive, as it will always put it on the hard disk.
However, if you already have the partition created on the SSD and then build the "Fusion" drive, it will keep it there and it works fine.
Hi guys,
From terminal, I can run diskutil list which gives me /dev/disk0 - 14! Disk 0 has 0-3 (0 Guid_partition_scheme, 1 EFI, 2 Apple_CoreStorage, 3 Apple_Boot ), Disk 1 has 0-3 (0 Guid_partition_scheme, 1 EFI, 2 Apple_CoreStorage, 3 Apple_Boot), Disk 2 has 0-2 (0 Apple_partition_scheme, 1 Apple_partition_map, 2 Apple_HFS), Disk 3-13 all have 0 which are 524.3 kb and are all untitled and finally Disk 14 has 0-1 (1 FDisk_partition_scheme, 2 Apple_Boot).
I then did the DIY Fusion with Terminal as posted many times ... Except, include the partition-# for the OS X partition on the SSD.
Rather than using disk0 disk1 ... Use disk0partition2 disk1 in the commands. Of course, the numbers are from your systems disk table for the SSD and hard disk to be joined.
Good luck ...
-howard
Ok i just successfully split my fusion drive into the SSD and HDD alone.
View attachment 384950
3TB HDD benchmark
View attachment 384948
128GB SSD benchmark
View attachment 384949
I managed today to disable fusion drive and keep separate drives. Thanks for the help in the other thread!
hello!
my imac should hopefully arrive on monday, and i dont want to use the ****** fusion drive.
after reading the thread, i am very happy, that people managed to disable fusion and use seperate drives!
could one of you guys, who successfully managed do do so, once more and in simple words explain, how to exactly- step by step- proceed to get 2 seperate drives on my new baby on monday!?!?
i would appreciate your help