Restoring fusion drive to default status!

jli93

macrumors newbie
Original poster
Feb 26, 2015
3
0
Hi there, I've mucked around with the drive accidentally in the past trying to do clean installs and just want to remove any partitions I've created or random and unused drives. I just want it to look and be like when I first opened it out the box if that makes sense. Its the iMac 21.5-inch with fusion drive.
I've uploaded what my disk utility and terminal look like.
Thanks!
 

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/V\acpower

macrumors 6502a
Jul 31, 2007
549
370
Well, the "basic rule" is that you boot up from another drive than the one you want to re-partition and format.

The simplest way would be to boot up from a USB stick.

This will help you create one that : http://arstechnica.com/apple/2014/10/how-to-make-your-own-bootable-os-x-10-10-yosemite-usb-install-drive/

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So, when you boot up from the USB stick, before (re) installing OS X, in the menu you will find the Disk Manager app and from there you will be able to select your Internal Drive (don't select a particular partition), and go into the partition menu, select 1 Partition and recreate your whole partition map.

Of course, you will lose your files and will need to reinstall OS X later. I assume that you have backups and that you know how to do all that.

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Also, about the "fusion drive", from what I can see in your picture, the Fusion Drive is still, well, "fusionned". So there is nothing particular you have to do about it.
 

marzer

macrumors 65816
Nov 14, 2009
1,329
44
Colorado
Hi there, I've mucked around with the drive accidentally in the past trying to do clean installs and just want to remove any partitions I've created or random and unused drives. I just want it to look and be like when I first opened it out the box if that makes sense. Its the iMac 21.5-inch with fusion drive.
I've uploaded what my disk utility and terminal look like.
Thanks!
According to your screenshots, there's nothing to reset regarding the Fusion Drive, you are operating a fully functional single-volume fusion drive as it looks from the factory. You're disk Utility is set to show invisible partitions, all partitions listed are typical for a Fusion Drive configure and will show up again even if you were to destroy and remake your fusion drive. I'd recommend you reset nothing with regards to your partitioning scheme. If you want a clean install, simply erase the drive and reinstall the OS and restore your data files.
 

jli93

macrumors newbie
Original poster
Feb 26, 2015
3
0
Hey thanks for the replies guys. Ok I'll leave it as is and just clean install Yosemite. One more question, what does mounting the drives do and is it ok to unmount them because I don't use them?
 

Alesc

macrumors 6502
Nov 11, 2014
253
11
France
According to your screenshots, there's nothing to reset regarding the Fusion Drive, you are operating a fully functional single-volume fusion drive as it looks from the factory. You're disk Utility is set to show invisible partitions, all partitions listed are typical for a Fusion Drive configure and will show up again even if you were to destroy and remake your fusion drive. I'd recommend you reset nothing with regards to your partitioning scheme. If you want a clean install, simply erase the drive and reinstall the OS and restore your data files.
After failing to partition my Fusion Drive with Bootcamp, I've repaired the disk and I've these information:


But I don't think it was like that out of the factory. When I found Fusion Drive screenshots on the internet, there is some free memory and "Capacity" and "Used" are different :



But I don't know if it is important...
 

jli93

macrumors newbie
Original poster
Feb 26, 2015
3
0
Hmm yeah the factory look seems to be cleaner and name on drive is different too. I've definetly changed things in the disk utility
 

marzer

macrumors 65816
Nov 14, 2009
1,329
44
Colorado
Hmm yeah the factory look seems to be cleaner and name on drive is different too. I've definetly changed things in the disk utility
The name of the logical group doesn't matter at all, no impact to its use or operation. It comes from the factory labeled "Macintosh HD" but that's not the actual default name, "Internal Drive" is the default. The only way to restore the name to "Macintosh HD" is to destroy the logical group and manually rename it as you rebuild the logical volume. Anytime Disk Utility rebuilds the Fusion Drive automatically, it will name the logical group "Internal Drive."

And the other pictures look cleaner because those shots aren't displaying hidden partitions. Turn off display hidden partitions in your disk utility and yours will look just as clean. ;)

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After failing to partition my Fusion Drive with Bootcamp, I've repaired the disk and I've these information:
Image

But I don't think it was like that out of the factory. When I found Fusion Drive screenshots on the internet, there is some free memory and "Capacity" and "Used" are different :

Image

But I don't know if it is important...
From those shots there's nothing obvious. Other than that's two different OS x versions (and numerical bases) which may be causing minor variations in how info is displayed.
 

Alesc

macrumors 6502
Nov 11, 2014
253
11
France
From those shots there's nothing obvious. Other than that's two different OS x versions (and numerical bases) which may be causing minor variations in how info is displayed.
OK, thanks :)
If sombody can make the screenshot of his 3TB Fusion Drive under Yosemite, that would be great :)
 

Alesc

macrumors 6502
Nov 11, 2014
253
11
France
Hi there!
If sombody can make the screenshot of his 3TB Fusion Drive like this under Yosemite, that would be very useful for me:




I wan't to compare and to know if I have succeed in retrieving my default Fusion Drive configuration after my failing attempt in partitionning my disk with Bootcamp.

Thanks :)
 

skyhawkmatthew

macrumors member
Oct 1, 2007
90
21
Australia
This is what my iMac with fusion drive shows - it hasn't been fiddled with at all:



Diskutil list reveals a few more hidden partitions, so I think what you're seeing with hidden partitions enabled in Disk Utility is probably normal. :)