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Old Dec 13, 2012, 04:20 PM   #26
MatthewAMEL
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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).
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Old Dec 13, 2012, 05:00 PM   #27
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Quote:
Originally Posted by MatthewAMEL View Post
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'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.
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Old Dec 13, 2012, 05:01 PM   #28
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Originally Posted by Khadgar View Post
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.
Did you use both commands, or did you follow the MacWorld link and only use the one command?

diskutil cs deleteVolume < insert fusion logical volume ID here >
diskutil cs delete < insert coreStorage logical volume group ID here >


These commands should automatically revert the individual drives back to normally formatted HFS+ condition and remove the Fusion volume reference from the disk table.
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Old Dec 13, 2012, 05:07 PM   #29
Khadgar
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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.
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Old Dec 13, 2012, 05:15 PM   #30
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Originally Posted by Khadgar View Post
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.
When it identified the problem, did you have the option to ignore and not re-Fusion the drive?

This was my fear, that the new Disk Utility might try to make Fusion drives out of any random SSD and hard disk it found in your system.

I will have a new iMac soon with the new versions of DU ... so maybe I can test this more.
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Old Dec 13, 2012, 05:23 PM   #31
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Nope. There was no option. I had to either fuse the drives or not install. I could, however, install it on any external drive I wished.

What it looks like is that the OS shipped with the system is set up specifically for the setup. When I can get a generalized one that works (unfortunately might likely be OS X 10.9) we might be able to pick and choose.
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Old Dec 13, 2012, 05:27 PM   #32
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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.
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Old Dec 13, 2012, 05:36 PM   #33
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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.
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Old Dec 13, 2012, 05:43 PM   #34
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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.
I don't want them fused either, i want to replace the normal HDD with a 512GB SSD and run that and the 128GB SSD separately. Hopefully someone finds a solution though i do remember reading that is has already been done, i will dig up the article.
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Old Dec 13, 2012, 06:29 PM   #35
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The MacWorld article also identifies this quirk:

http://www.macworld.com/article/2015...ion-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
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Old Dec 13, 2012, 10:15 PM   #36
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The MacWorld article also identifies this quirk:

http://www.macworld.com/article/2015...ion-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
Howard,

You have had some great insights, but I'm wondering if the factory built Fusion isn't turning into an unmitigated disaster.

My iMac isn't due to ship until Jan 7th. Hopefully someone will figure out the mechanism Disk Utility and the installer are using to 'recognize' the broken fusion drive.

Makes me happy I splurged for the SSD.
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Old Dec 14, 2012, 07:51 AM   #37
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Any further info on this? My iMac arrives on Monday and im keen to install my own 512GB SSD and disable fusion.
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Old Dec 14, 2012, 09:15 AM   #38
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"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.
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Old Dec 14, 2012, 04:33 PM   #39
torana355
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"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.
Damb it, ah well i guess i will have to put up with fusion until a solution is found, i am interested to see how well it works anyway.
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Old Dec 16, 2012, 12:33 AM   #40
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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?
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Old Dec 16, 2012, 01:27 AM   #41
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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?
ROG on this forum has experimented and you can disable fusion only if you add a second SSD. This happens to be my plan anyway so im happy. If you have an SSD and HDD they will be automatically fused together.
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Old Dec 16, 2012, 05:16 PM   #42
torana355
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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.
Ok i knew this had been done, you have to split the drive using the two commands, you CANNOT use DU from the recovery partition as it will try to repair the fusion drive, just install ML and it gives you the options of the two separate disks to install too.
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Old Dec 18, 2012, 01:17 PM   #43
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Help! Looks like I messed up the fusion drive

Hi guys,

Just received my 2012 imac 27" with the 1tb fusion drive and it looks like I "broke" it. I hope that some of you guys more proficient in OSX could help me with my problem!

I followed Howard's links to Macworld and used the 1 step to break fusion drive. (I should have read more carefully about the 2 steps - is this part of my issue to come?) Then I reinstalled OSX. I then used bootcamp to split the 128 ssd into equal partitions and installed Windows 7. I also partitioned the 1 TB drive equally between OSX HFS and Win7 NTFS.

This morning I decided I wanted to enlarged the partition of Windows 7 so I went to disk utility and reduced OSX from 60gb to 40gb which left a blank 20gb partition in addition to the 60gb Windows 7 partition.

I went to Windows 7 and right clicked on the windows 7 partition but no option to extend partition was available. I clicked on the 20gb partition and tried formatting to NTFS. Again, clicking on the windows 7 partition did not give an option to extend partition. However, clicking on the NTFS partition did allow it to be extended. I didn't continue from this point and after reading about several programs to extend partitions, I decided to reboot to OSX.

Upon rebooting holding option, I only had the option to boot into windows and recovery osx. The OSX partition was gone. I choose the recovery osx. I then went to Disk Utility and discovered that there was no OSX. The SSD drive listed as disk0 and disk 1 were in red and the 1tb drive was also in red.

Clicking on any of the disks asked for a prompt to "fix" and erase all drives.

Finally I clicked yes and disk utility went to work -- however, after 30 minutes it stopped responding and was about 70% complete. I restarted the system and internet recovery started.

In internet recovery, I ran disk utility which shows a single drive of 1.12 tb - if I verify or repair - everything comes out okay and in green. However, when I select reinstall osx, there is no drive to install from.

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 need your help because I do not know what to do to reinstall OSX and fix my system!

My questions are several fold:

(1) how do i reinstall osx? (do i need to fix anything in the drives?)
(2) i would like to have osx and windows 7 on the sad -- should i do what i did before?
(3) howard, you mentioned you could have fusion drive enabled with ?bootcamp if the ?bootcamp? partition was already created -- what the steps to do this? how do i install win7 to the correct partition?

Thank you all - I really appreciate any suggestions and support you can offer.

-jay

Update 1: Reading carefully the partition tab - it says -- this partition contains a locked disk and can not be resized until it is unlocked.

Update 2: Using the same commands to break the fusion drive -- diskutility corestorage delete the logical disk breaks the fusion drive and now the two hard drives appears as separate and osx installer sees both hard drives as available for installation.

Update 3: After remaking the fusion drive, I erased it then broke it using the 2 commands howard posted, now I'm installing using the remote install option.

Update 4: I reinstalled OSX and Win7 on different partitions -- however, I'm trying to redo the fusion drive -- I can't figure out how to get the bootcamp partition recognized and protected after rejoining the OSX (40g) on SSD with the 1TB hard drive. I wonder if Howard could give some insight here:

Quote:
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.
Update: 5 - I can't figure out how to join the OSX partition on the SSD with the 1 TB hard drive which preserves the bootcamp SSD partition. Since it's taking forever to download mountain lion for each reinstall, I've decided just to not use fusion drive and keep the SSD and HD separate and in separate partitions - it's safer in the long run for integrity of data since fusion drive isn't true caching. Might consider enabling fusion if / when someone figures out how to keep Win7 Bootcamp on the SSD.


Last edited by talisabt; Dec 19, 2012 at 02:18 PM.
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Old Dec 20, 2012, 10:17 PM   #44
torana355
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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 just did a diskutil list on my 27" 3TB fusion imac and it also has 14 disks???
Anyway i deleted the fusion volume and then the logical volume and i am now installing OSX on the SSD only.
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Old Dec 20, 2012, 11:13 PM   #45
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Dividing a 128GB drive for two operating systems may not leave enough room for Fusion to work properly, I used a 256GB drive (remember there is a write buffer on the SSD too).

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
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Old Dec 20, 2012, 11:16 PM   #46
torana355
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Ok i just successfully split my fusion drive into the SSD and HDD alone.

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3TB HDD benchmark

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128GB SSD benchmark

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ID:	384949
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Old Dec 21, 2012, 12:48 PM   #47
talisabt
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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

That's the key! Thanks Howard.

I have stuck to not using fusion and keeping the drives separate -- the main reason is that I don't have a mountain lion dvd / usb (made one - doesn't work with the new iMac) -- and it takes 2 hours+ per download of mountain lion to reinstall... 2 days of this was enough for me! However, everything works great with the 2 drives separate!

I think this is exactly the info many macrumor readers are looking for.

Yes, you can have bootcamp on the fusion drive!

Step 1. Boot into recovery mode using Command - R --- Separate your fusion drive into SSD and HD using the 2 commands Howard listed
Step 2. Boot into OSX normally -- Install your bootcamp windows 7 on the SSD
Step 3. Boot into recovery mode using Command - R -- Join your SSD and HD using disk0partition2 disk1 as per howards instructions.
Step 4. Boot into recovery mode using Command - R -- reinstall OSX via internet


Hopefully Apple will release Mountain Lion for the new imac which we can have on a USB stick.. will save hours and hours of frustration.
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Old Dec 21, 2012, 04:33 PM   #48
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Ok i just successfully split my fusion drive into the SSD and HDD alone.

Attachment 384950

3TB HDD benchmark

Attachment 384948

128GB SSD benchmark

Attachment 384949
I managed today to disable fusion drive and keep separate drives. Thanks for the help in the other thread!
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Old Dec 22, 2012, 05:10 PM   #49
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please help

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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
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Old Dec 23, 2012, 07:16 PM   #50
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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
http://arstechnica.com/apple/2012/11...-fusion-drive/

Follow this article, especially page 2. Boot in recovery mode, then open terminal, and type these commands:

diskutil cs list

This command will show you the IDs you need to delete fusion drive.

diskutil cs deleteVolume < insert fusion logical volume ID here >
diskutil cs delete < insert coreStorage logical volume group ID here >


These commands will split the drives apart. Once the drives are separated, you can rename those drives in Terminal, because you can't use Disk Utility: it will try to fix the Fusion Drive for you.

diskutil list

This command will show you the identifier for the two drives, that you'll use this way:

diskutil rename disk0s2 Macintosh\ HD
diskutil rename disk1s2 Data\ HD
(The backslash is needed to write the space in Terminal)

Exit terminal, click on "Install OS X" and select the SSD, and you're good to go. Once in disk utility in OSX, the drives will be listed normally.

Last edited by themcfly; Jun 17, 2013 at 03:34 AM.
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