The Fusion Drive is made up of two physical drives in the 2012 Mac mini is two SATA drives one small SSD and one HDD!
In the newer 2014 it’s made up of a PCIe blade SSD and a SATA HDD.
But before you can alter the drive set you first need to break the fusion drive by running [https://www.macworld.com/article/2015664/storage-flash/how-to-split-up-a-fusion-drive.html|How to split up a Fusion Drive] for the older Sierra and [https://www.lifewire.com/split-fusion-drive-apart-2260166|Split Your Fusion Drive Apart] gets into the newer macOS’s.
And lastly, here’s a detailed writeup on Core Storage: [http://public.z-effects.com/CoreStorageTraining.pdf|Understanding Core storage, logical volumes, and Fusion drives]
Now here’s the steps you’ll need to do:
Create a Bootable USB thumb drive I would recommend sticking with Sierra as it works better with the older SATA drives (using HPFS+ file system) or if you really need a newer OS I would stay with Mojave for now as Catalina still has some deep issues hopefully the update will address (migrating to the newer APFS file system).
[https://www.macworld.com/article/3092900/how-to-create-a-bootable-macos-sierra-installer-drive.html|How to create a bootable macOS Sierra installer drive]
+
+
Apple messed up the installer files [https://appleinsider.com/articles/19/10/24/if-youve-got-an-old-macos-install-image-it-will-probably-stop-working-today|If you've got an old macOS install image, it will probably stop working today] so you’ll need to get a fresh one from here: [https://support.apple.com/en-us/HT208202|How to upgrade to macOS Sierra| or [https://support.apple.com/en-us/HT210190|How to upgrade to macOS Mojave] jump to Step 4 for the link in either.
If you haven’t make a backup of your user accounts, apps & data to an external drive
Using the created thumb drive boot up the system pressing the Option key to get to the Startup manager to select the thumb drive.
Now reformat the drives using Disk Utility and install the OS using the OS installer app onto the SSD drive. Don’t use cloning software it just makes a mess! I haven’t used cloning software on boot drives for over 12 years! As it has made more of a mess than doing its as Apple intended! Now with the newer APFS its worse and it often doesn’t create the hidden recover partition either. Find a trash bin and toss it out.
Now restore your user accounts and apps to the SSD drive. You really don’t want to load it up with stuff! Leave at least 1/3 of it free. At the end of the OS install process you’ll be asked if you have data to restore you can do it then or after applying your OS updates you can open up Migration Assistant app in the Apps/Utilities folder.
Now setup the second drive using Disk Utility and now restore your user data over to the HDD drive.
I would recommend using TimeMachine to backup your stuff and then use Migration Assistant to restore your stuff back
'''Here’s more details:'''
* [https://www.youtube.com/watch?v=geJiTXOb37w|How to back up your Mac with Time Machine — Apple Support]
* [https://support.apple.com/en-us/HT201250|Back up your Mac with Time Machine]
* [https://support.apple.com/en-us/HT204350|How to move your content to a new Mac]
* [https://www.imore.com/how-to-transfer-old-mac-data-new-mac|How to transfer your old Mac's data to your new Mac]
OK, lets clear the confusions:
The Fusion Drive is made up of two physical drives in the 2012 Mac mini is two SATA drives one small SSD and one HDD!
In the newer 2014 it’s made up of a PCIe blade SSD and a SATA HDD.
But before you can alter the drive set you first need to break the fusion drive by running [https://www.macworld.com/article/2015664/storage-flash/how-to-split-up-a-fusion-drive.html|How to split up a Fusion Drive] for the older Sierra and [https://www.lifewire.com/split-fusion-drive-apart-2260166|Split Your Fusion Drive Apart] gets into the newer macOS’s.
And lastly, here’s a detailed writeup on Core Storage: [http://public.z-effects.com/CoreStorageTraining.pdf|Understanding Core storage, logical volumes, and Fusion drives]
Now here’s the steps you’ll need to do:
Create a Bootable USB thumb drive I would recommend sticking with Sierra as it works better with the older SATA drives (using HPFS+ file system) or if you really need a newer OS I would stay with Mojave for now as Catalina still has some deep issues hopefully the update will address (migrating to the newer APFS file system).
[https://www.macworld.com/article/3092900/how-to-create-a-bootable-macos-sierra-installer-drive.html|How to create a bootable macOS Sierra installer drive]
If you haven’t make a backup of your user accounts, apps & data to an external drive
Using the created thumb drive boot up the system pressing the Option key to get to the Startup manager to select the thumb drive.
Now reformat the drives using Disk Utility and install the OS using the OS installer app onto the SSD drive. Don’t use cloning software it just makes a mess! I haven’t used cloning software on boot drives for over 12 years! As it has made more of a mess than doing its as Apple intended! Now with the newer APFS its worse and it often doesn’t create the hidden recover partition either. Find a trash bin and toss it out.
Now restore your user accounts and apps to the SSD drive. You really don’t want to load it up with stuff! Leave at least 1/3 of it free. At the end of the OS install process you’ll be asked if you have data to restore you can do it then or after applying your OS updates you can open up Migration Assistant app in the Apps/Utilities folder.
Now setup the second drive using Disk Utility and now restore your user data over to the HDD drive.
I would recommend using TimeMachine to backup your stuff and then use Migration Assistant to restore your stuff back
'''Here’s more details:'''
* [https://www.youtube.com/watch?v=geJiTXOb37w|How to back up your Mac with Time Machine — Apple Support]
* [https://support.apple.com/en-us/HT201250|Back up your Mac with Time Machine]
* [https://support.apple.com/en-us/HT204350|How to move your content to a new Mac]
* [https://www.imore.com/how-to-transfer-old-mac-data-new-mac|How to transfer your old Mac's data to your new Mac]