Help to create fusion drive, OS X Mojave

Question

Help to create fusion drive, OS X Mojave

Hi,

I would be very grateful for any help to create a fusion drive.

Presently on my late 2012 iMac I am running OS X Mojave installed on a 120gb external SSD.

Ideally, combining the 1tb internal hard drive and the external SSD into a fusion drive.

I would welcome any help with instructions to complete the above or be pointed in the right direction to obtain detailed instructions to create the fusion drive.

thanking the community in advance.

Best regards, Graham

PS> I hope I have posted in the correct community.

iMac, macOS Mojave (10.14), Late 2012 27" iMac,3.2 GHz

Posted on Sep 28, 2018 9:25 AM

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Answer 1

JimmoV

Level 1

9 points

Sep 29, 2018 1:06 AM in response to Graham_Brazendale

This worked for me. Most stuff done in Terminal.app

The disk ID, mount points and names are arbitrary. DO not enter the commands verbatim.

Read through the following and if EVERYTHING makes sense to you then good. Otherwise educate yourself first.

diskutil list

finds this in regard to 2 APFS freshly formatted disks (one spinning disk HDD plus one SSD):

HDD Container disk3s2

HDD disk5

SSD Container disk0s2

SSD disk4

next do this:

diskutil coreStorage create FUSION /dev/disk4 /dev/disk5

result on screen:

Core Storage LVG UUID: 274C3C09-0526-4B3A-8C14-3BB207EF6FFF

next do this

diskutil coreStorage createVolume 274C3C09-0526-4B3A-8C14-3BB207EF6FFF jhfs+ FusionVolume 100%

after that convert to APFS with Disk Utility.app

Then clone your boot disk with CCC5 to the new Fusion Disk. Done.

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Answer 2

knosis

Level 1

8 points

Oct 4, 2018 10:02 AM in response to Graham_Brazendale

I think you may have to clone Mojave using CCC5 to your APFS fusion drive first. Then use migration assistant to move your user and apps to the Fusion Drive Mojave. I'm going to try this but haven't been able to. I got as far as you did trying to install Mojave from the installer. I don't think the installer will work.

Apple becomes more like Microsoft every day. 😟

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Answer 3

dialabrain

Level 10

137,403 points

Sep 28, 2018 9:28 AM in response to Graham_Brazendale

Here's info on repairing a split Fusion drive. I don't know if it would work on an internal and external drive.

How to fix a split Fusion Drive - Apple Support

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Answer 4

Sep 30, 2018 2:29 AM in response to JimmoV

Good Morning, your instructions worked perfectly, except, I then started to install OS X Mojave which got through first part and then stalled.

Really disappointe, but anyway I opened up disk Utility and the Fusion Volume was not displayin, just showing as separate drives.

‘APFS Physical store disk0s2 internal” and “APFS Physiscal store disk3s2 external”

Sorry to be a pain, but have you or any one else, any ideas to fix this (hopefully) final hurdle!

thanks again, Graham

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Answer 5

Oct 4, 2018 11:44 AM in response to knosis

Hi, thanks indeed for your response, much appreciated.

I will give it a try, although it means purchasing CCC5.

i can’t help feeling disappointed that the Fusion drive is not robust enough not to act like a normal drive.

Best regards, Graham.

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Answer 6

Sep 28, 2018 10:40 AM in response to dialabrain

Hi,

thank you you for replying, I don’t know if the instructions will work with an external drive, but worth a try if there are no other observations.

Thanks again, much appreciated. Regards Graham

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Answer 7

dialabrain

Level 10

137,403 points

Sep 28, 2018 10:41 AM in response to Graham_Brazendale

You're welcome.

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Answer 8

Sep 29, 2018 1:12 AM in response to JimmoV

Thanks indeed. I can certainly follow your instructions and the first to refer to formatting in APFS.

I will give it a try, many thanks.

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Answer 9

Sep 28, 2018 12:14 PM in response to Graham_Brazendale

An important thing to remember is that before you can create a Fusion Drive, both drives to be in the Fusion Drive will need to be erased. So the first step must be a full backup. I suggest that the backup be a bootable clone. This will be needed so that you can boot from it to create the new Fusion Drive on the other drives which will make up the Fusion Drive.

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Help to create fusion drive, OS X Mojave

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