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Suggested readers looking for a solution to directly read the answer that I posted with the step by step procedure.

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edited Jun 8, 2023 at 18:24

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I could find a solution to how recreate a fusion drive and a "Macintosh HD" volume so that OS X can be reinstalled. I suggest to people facing similar issue to simply read the answer that I posted to my own question, which will provide them a step by step procedure.

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asked Jun 6, 2023 at 11:06

OuzoPower

How to create a Fusion drive that is not a Core Storage?

I need to reinstall MacOS X Mojave on an iMac iMac 27'' 2019 (A2115 EMC 3194).

Because of corrupted fusion data structures, the fusion drive was not visible from the installer, so that I had to reset the SSD and HDD:

dd if=/dev/zero of=/dev/disk0 (fully wipes the SSD)
dd if=/dev/zero of=/dev/disk1 count=1 (wipes MBR of HDD)

Above commands made both drives visible from the Disk Utility. (They were previously hidden by the Fusion drive container.) Then, from the Disk Utility, the two drives were erased and formatted in APFS, with GPT partition scheme.

Strangely, diskutil resetFusion detects the logical volumes from the SSD and HDD but is unable to detect the solid state drive as a physical drive. (The order of disks is inverted here, but we see that the disk1 of the SSD is not listed.)

-bash-3.2# diskutil resetFusion

Internally-located hardware disk device known to the currently-running macOS:
Rotational                               (disk0)

Volumes exported by partitions or storage systems hosted on the above device:
SSD SM0032L                              (disk3s1)
HDD ST1000DM003                          (disk4s1)

Your computer must have exactly 1 solid-state and 1 rotational disk drive

How to fuse the APFS partitions ? Here's the current scheme.

-bash-3.2# diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                 Apple_APFS Container disk4         1000.0 GB  disk0s2

/dev/disk1 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         28.0 GB    disk1
   1:                        EFI EFI                     314.6 MB   disk1s1
   2:                 Apple_APFS Container disk3         27.7 GB    disk1s2

/dev/disk2 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        +2.1 GB     disk2
   1:                  Apple_HFS macOS Base System       2.0 GB     disk2s1

/dev/disk3 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +27.7 GB    disk3
                                 Physical Store disk1s2
   1:                APFS Volume SSD SM0032L             20.5 KB    disk3s1

/dev/disk4 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1000.0 GB  disk4
                                 Physical Store disk0s2
   1:                APFS Volume HDD ST1000DM003         20.5 KB    disk4s1
(...)

Should I use logical volume commands, delete the synthetized volumes of disks 3 and 4 and then create from the command line the volume of disk3 according to the original scheme here below?

I know how to use gpt commands to show and edit the gpt tables.

Here was the original situation:

-bash-3.2# diskutil list
/dev/disk0 (internal):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                         28.0 GB    disk0
   1:                        EFI EFI                     314.6 MB   disk0s1
   2:                 Apple_APFS Container disk3         27.7 GB    disk0s2

/dev/disk1 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *1.0 TB     disk1
   1:                        EFI EFI                     209.7 MB   disk1s1
   2:                 Apple_APFS Container disk3         1000.0 GB  disk1s2

/dev/disk2 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        +2.1 GB     disk2
   1:                  Apple_HFS macOS Base System       2.0 GB     disk2s1

/dev/disk3 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +1.0 TB     disk3
                                 Physical Stores disk0s2, disk1s2
   1:                APFS Volume Preboot                 185.9 MB   disk3s2
   2:                APFS Volume Recovery                510.6 MB   disk3s3
   3:                APFS Volume VM                      2.1 GB     disk3s4
   
(...)

macos fusion-drive