Hi.
I have an iMac 2015 with a 2 TB Fusion drive. My Mac has started to slow considerably and I would like to reset/reinstall Mojave and start fresh.
The question I have is: when I erase the HD do I need to do anything additional to take in account the 128gb Fusion drive? Or does the installer just count the volumes as the same?
iMac 27", macOS 10.14
you don't need to anything when you format the fusion drive, you can just go to recovery mode (cmd+R) and re-install OS in it.
If you format your drives individually then you need to combine your drives and re-install OS, below are the commands for creating a fusion drive:
to find out physical storage volumes
diskutil list
to create Fusion drive:
diskutil coreStorage create "Macintosh HD” /dev/disk0 /dev/disk1
to create logical volume:
diskutil coreStorage createVolume lvgUUID JHFS+ “Macintosh HD” 100%
you don't need to anything when you format the fusion drive, you can just go to recovery mode (cmd+R) and re-install OS in it.
If you format your drives individually then you need to combine your drives and re-install OS, below are the commands for creating a fusion drive:
to find out physical storage volumes
diskutil list
to create Fusion drive:
diskutil coreStorage create "Macintosh HD” /dev/disk0 /dev/disk1
to create logical volume:
diskutil coreStorage createVolume lvgUUID JHFS+ “Macintosh HD” 100%
Thank you for your reply. That’s good to know.
Just one more question. For Mojave and Fusion do I need to format still in Extended? Or should I use APFS?
Once you update, even if the format is in Extended it will be converted to APFS by default as Mojave needs APFS.
Superb. Thanks again for your help.
Factory reset/fresh install - Fusion drive
