IMac 27 How to restore a SSD made invisible after formatting a fusion drive from APFS to HFS+

fusion-drivehfs+ssd

I bought a used Imac 27 with APFS fusion drive mOdel Identifier iMac15,1 before discovering the previous owner had replaced the original 512 Gb SSD by third party one with an adapter. After formatting the fusion drive back to HFS+ with disk utility, and installing OSX 10.12.6 (Sierra) with my previous data from my older computer, the SSD became invisible both in disk utility and diskutil (see the first lines of the "disk utility list" command. I have made additional investigations, and determined that booting from a High sierra or above OS the SSD is again visible, and I was able to partition it, make an HFS+ Fusion drive with the HDD or a partition of the HDD, etc all operations appearing normal. However when booting again from Sierra, neither the SDD nor the Fusion drive are visible in diskutil or disk utility. I want to stick to Sierra for a number orf reasons including compatibilty with other older machines. How could I restore the SSD to become visible and useful again ? Just below are the first lines of the result of the command system_profiler SPSerailATADataType (after upgrading again to OS 10.15.5
system_profiler SPSerialATADataType
SATA/SATA Express:

Intel 8 Series Chipset:

  Vendor: Intel
  Product: 8 Series Chipset
  Link Speed: 6 Gigabit
  Negotiated Link Speed: 6 Gigabit
  Physical Interconnect: SATA
  Description: AHCI Version 1.30 Supported

    ST4000DM006-2G5107:

      Capacity: 4 TB (4 000 787 030 016 bytes)
      Model: ST4000DM006-2G5107                      
      Revision: DN04    
      Serial Number: ZC19X1NJ
      Native Command Queuing: Yes
      Queue Depth: 32
      Removable Media: No
      Detachable Drive: No
      BSD Name: disk1
      Rotational Rate: 7200
      Medium Type: Rotational
      Partition Map Type: GPT (GUID Partition Table)
      S.M.A.R.T. status: Verified
      Volumes:
        EFI:
          Capacity: 209,7 MB (209 715 200 bytes)
          File System: MS-DOS FAT32
          BSD Name: disk1s1
          Content: EFI
          Volume UUID: 0E239BC6-F960-3107-89CF-1C97F78BB46B
        disk1s2:
          Capacity: 4 TB (4 000 577 273 856 bytes)
          BSD Name: disk1s2


-bash-3.2# diskutil list
/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *4.0 TB     disk0
   1:                        EFI EFI                     209.7 MB   disk0s1
   2:                  Apple_HFS HD1-IMAC27              4.0 TB     disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3

/dev/disk1 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        +2.1 GB     disk1
   1:                  Apple_HFS OS X Base System        2.0 GB     disk1s1

/dev/disk2 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                            untitled               +5.2 MB     disk2

Below is the result from the two commands issued in OS High Sierra after successful creation of a Fusion drive formatted in HFS+ and with one partition of the HD.
Yves:Imac-27- ~ yves$ system_profiler SPHardwareDataType
Hardware:

Hardware Overview:

  Model Name: iMac
  Model Identifier: iMac15,1
  Processor Name: Intel Core i7
  Processor Speed: 4 GHz
  Number of Processors: 1
  Total Number of Cores: 4
  L2 Cache (per Core): 256 KB
  L3 Cache: 8 MB
  Memory: 32 GB
  Boot ROM Version: 235.0.0.0.0
  SMC Version (system): 2.23f11
  Serial Number (system): C02NLC33FY14
  Hardware UUID: 7791AAC4-ED40-53C8-AA90-41C48B10DD89

Imac-27-Yves:~ yves$ diskutil list
/dev/disk0 (internal, physical):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme *4.0 TB disk0
1: EFI EFI 209.7 MB disk0s1
2: Apple_HFS HD2-27 2.0 TB disk0s2
3: Apple_Boot Recovery HD 650.0 MB disk0s3
4: Apple_CoreStorage Macintosh HD 2.0 TB disk0s4
5: Apple_Boot Recovery HD 650.0 MB disk0s5

/dev/disk1 (internal):
#: TYPE NAME SIZE IDENTIFIER
0: GUID_partition_scheme 512.1 GB disk1
1: EFI EFI 209.7 MB disk1s1
2: Apple_CoreStorage Macintosh HD 511.8 GB disk1s2
3: Apple_Boot Boot OS X 134.2 MB disk1s3

/dev/disk2 (internal, virtual):
#: TYPE NAME SIZE IDENTIFIER
0: Apple_HFS Macintosh HD +2.5 TB disk2
Logical Volume on disk1s2, disk0s4
582B2901-BB86-47DC-857E-14E742AED9F9
Unencrypted Fusion Drive

Best Answer

I have not exactly identified the source of the problem, but after upgrading to High Sierra (OSX 10.13.6), everything went back to normal behavior. I could see the SSD again, format it, and combine it with the HD into a new fusion drive formatted in HFS+, as was the original disk setup of the computer.

Imac-27-Yves:~ yves$ diskutil list

/dev/disk0 (internal): #: TYPE NAME SIZE IDENTIFIER 0: GUID_partition_scheme 512.1 GB disk0

1: EFI EFI 209.7 MB disk0s1

2: Apple_CoreStorage Macintosh HD 511.8 GB disk0s2

3: Apple_Boot Boot OS X 134.2 MB disk0s3

/dev/disk1 (internal, physical): #: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *4.0 TB disk1

1: EFI EFI 209.7 MB disk1s1

2: Apple_HFS HD2-27 2.0 TB disk1s2

3: Apple_Boot Recovery HD 650.0 MB disk1s3

4: Apple_CoreStorage Macintosh HD 2.0 TB disk1s4

5: Apple_Boot Recovery HD 650.0 MB disk1s5

/dev/disk2 (internal, virtual): #: TYPE NAME SIZE IDENTIFIER

0: Apple_HFS Macintosh HD +2.5 TB disk2

                             Logical Volume on disk0s2, disk1s4

                             582B2901-BB86-47DC-857E-14E742AED9F9
                             Unencrypted Fusion Drive

Related Solutions

I think I messed up the Fusion Drive on the 1TB iMac (with BootCamp)

Theoretically everything is fine with your Fusion Drive. Fusion Drives look like this. Disk0 is your SSD with 121 GB and disk1 is your HDD with ~1 TB (~1.121 TB summed up).

The larger parts of your SSD (disk0s2) and your HDD (disk1s2) are pooled to a CoreStorage LVG (Fusion Drive: disk3) with a size of 967.8 GB. The rest is reserved for EFIs, a Recovery HD (alltogether ~1.3 GB) and your old Windows partition - now probably free space (~152 GB).

The logical volume 'Macintosh HD' (967.8 GB) spans disk0s2 and disk1s2. This is the first 'Macintosh HD' in picture 1. The volume 'Macintosh HD' - it's the one visible on the desktop - should ideally also have about 967.8 GB. This is the second 'Macintosh HD' in picture 1.
In fact it has only 852.67 GB (see picture 3).

In the second picture the logical volume 'Macintosh HD' is the first listed in black, the volume 'Macintosh HD' is the second listed in black, the other two 'Macintosh HD's listed in grey are the parts of your SSD and HDD dedicated to the logical volume 'Macintosh HD'.

In my opinion something went wrong after deleting various partitions with the Bootcamp Assistant/Disk Utility or in Windows.

Preparation:

Detach any external drive (especially your external Time Machine backup drive)
Restart to Internet Recovery Mode by pressing alt cmd R at startup.
The prerequisites are the latest firmware update installed, either ethernet or WLAN (WPA/WPA2) and a router with DHCP activated.
On a 50 Mbps-line it takes about 4 min (presenting a small animated globe) to boot into a recovery netboot image which usually is loaded from an apple/akamai server.

I recommend ethernet because it's more reliable. If you are restricted to WIFI and the boot process fails, just restart your Mac until you succeed booting.

Alternatively you may start from a bootable installer thumb drive (preferably Mavericks or Yosemite) or a thumb drive containing a full system (preferably Mavericks or Yosemite).

Now you may either repair CoreStorage or rebuild your Fusion Drive:

'Repair CoreStorage' (not recommended):

First i would try to check the volume 'Macintosh HD' with Disk Utility. If the volume is corrupted consider a reinstall of Mac OS X.
If the volume is ok quit Disk Utility
Open Terminal and enter diskutil unmountDisk /dev/LVIdentifier and both diskutil unmountDisk /dev/DiskContainingApple_CoreStorageIdentifier
In your case: first diskutil unmountDisk /dev/disk3 then diskutil unmountDisk /dev/disk0 and diskutil unmountDisk /dev/disk1
remove the EFI NO NAME partition with gpt remove -i IndexNumberOfEFINoName DiskIdentifier:
gpt remove -i 4 disk1
Remount the CoreStorage disks and then the Logical Volume:
In your case: first diskutil mountDisk /dev/disk0 and diskutil mountDisk /dev/disk1 and then diskutil mount /dev/disk3.

enter gpt -r -vvv show /dev/diskIdentfierOfApple_CoreStorage to get infos of your HDD CoreStorage disk.
In your case: gpt -r -vvv show /dev/disk1
It should look like this:

-bash-3.2# gpt -r -vvv show /dev/disk1
gpt show: /dev/disk1: mediasize=1000204886016; sectorsize=512;         blocks=1953525168
gpt show: /dev/disk1: PMBR at sector 0
gpt show: /dev/disk1: Pri GPT at sector 1
gpt show: /dev/disk1: GPT partition: type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, start=40, size=409600
gpt show: /dev/disk1: GPT partition: type=53746F72-6167-11AA-AA11-00306543ECAC, start=409640, size=1671210848
gpt show: /dev/disk1: GPT partition: type=426F6F74-0000-11AA-AA11-00306543ECAC, start=1671620488, size=1269760
gpt show: /dev/disk1: Sec GPT at sector 1953525167                               
     start          size  index contents                                        
         0             1        PMBR                                            
         1             1        Pri GPT header                                  
         2            32        Pri GPT table                                   
        34             6
        40        409600      1 GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
    409640    1671210848      2 GPT part - 53746F72-6167-11AA-AA11-00306543ECAC
1671620488       1269760      3 GPT part - 426F6F74-0000-11AA-AA11-00306543ECAC
1672890248     280634887
1953525135            32        Sec GPT table
1953525167             1        Sec GPT header

The free space on your HDD has 280634887 blocks. Please calculate the biggest block number dividable through 8. That's 280634880 blocks (á 512 bytes) which equals 143685058560 B or ~143.7 GB. Add the size of your HDD CoreStorage Physical Volume (852666400768 B) The result is 143685058560 B + 852666400768 B = 996351459328 B
Resize your HDD CoreStorage physical volume with diskutil cs resizeDisk HDDPVUUID newsize
In your case: diskutil cs resizeDisk 93892BE8-2B7F-4ABD-A4C3-984495DCD98D 996351459328b
Calculate the maximal size of your CoreStorage Logical Volume in diskutil cs list: (size disk0s2) + (size disk1s2) In your case that's 120988852224 B + 996351459328 B = 1117340311552 B. That should be the size of your refreshed Logical Volume Group.
Resize your Logical Volume with diskutil cs resizeVolume LVUUID LVGSize-128 MB In your case that's diskutil cs resizeVolume D237FFDC-7DA4-41D7-AC13-4CC7E5E8C0A0 1117212311552b. If you get an error (There is not enough free space...) choose a smaller size like 1117148311552b.
Quit Terminal and open Disk Utility.
Check your expanded CoreStorage Volume for errors.
Quit Disk Utility, choose your CS volume as startup disk and restart your Mac

'Rebuild Fusion Drive' (recommended if you have a Time Machine backup)

Booted to Internet Recovery Mode open Utilities → Terminal in the menubar and enter:
diskutil cs list to get the CoreStorage listing.
Copy the Logical Volume UUID, it's the fifth listed.
Now delete the Logical Volume with diskutil cs deleteVolume LVUUID.
In your case: diskutil cs deleteVolume D237FFDC-7DA4-41D7-AC13-4CC7E5E8C0A0.
Copy the Logical Volume Group UUID, it's the first listed in the listing of diskutil cs list.
Then delete the Logical Volume Group with diskutil cs delete LVGUUID.
In your case: diskutil cs delete 1EFE58BC-3613-44C4-86EE-D816F3B66E3E
Enter exit and quit 'Terminal'
Open 'Disk Utility'. Enter 'Ignore' if you are asked to fix the drives.
Choose your SSD and partition it: 1 Partition Mac OS X Extended (Journaled), hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~121 GB

Example:
Choose your HDD and partition it: 1 Partition Mac OS X Extended (Journaled), hit the Options button and choose GUID Partiton table and hit OK and Apply.
Please check that the size is ~1 TB

Example:
Quit Disk Utility and open Terminal
Enter diskutil list

Example (your disk identifiers and sizes are different of course: Your volume SSD probably has the Identifier disk0s2 and the size 121 GB and your volume HDD probably has the Identifier disk1s2 and the size 1.0 TB):
Enter diskutil cs create "Name" IdentifierSSD IdentifierHDD
In your case probably diskutil cs create "Macintosh HD" disk0s2 disk1s2.

Copy the resulting LVGUUID

Example:
Enter diskutil cs CreateVolume LVGUUID jhfs+ "Macintosh HD" 100%.

Example:
Enter diskutil cs list
Check the size of your Logical Volume. It should have the size ~1.121 TB

Example:
Quit Terminal
Open 'Disk Utility' and check your newly created volume for errors
Quit 'Disk Utility'
Attach your external Time Machine backup drive or check this answer if you use NAS or another network share.
Open 'Restore from Time Machine Backup'
Choose the appropriate Time Machine backup and restore your system
Reboot to your restored system.
Unmount and detach your Time Machine backup drive
Open 'Terminal' and enter 'diskutil list'
Check if your 'Recovery HD' is listed.
If your 'Recovery HD' is missing, usually reinstalling your current system with the latest available system installer (e.g. 'Install OS X Mavericks (10.9.5)' if Mavericks is currently installed) will recreate it without loosing any data. AFAIK Recovery Partition Creator 3.8 will NOT create a Recovery HD on CoreStorage volumes.
After reinstalling the system with the latest available system installer open App Store and install the latest security fixes.

Restoring Fusion Drive after error on partition erase

The way to deal with this is by separating the fusion drive, reformatting each drive, and recreating them. I suspect what's happened is your Mac cannot recognize the NTFS formatted portion of the disk.

Reboot while holding Alt + Cmd + R for Internet Recovery Mode. Go to Utilities > Terminal, and in terminal type: diskutil cs list, then find the UUID under "Logical Volume Group" with the missing space, copy it, and paste it after: diskutil cs delete. Go back to Disk Utility. At the prompt, click "OK" to repair your Fusion Drive. Exit Disk Utility, reboot (to the recovery partition if it doesn't automatically, to Internet Recovery Mode, or using a recovery USB drive) and reinstall OS X. When that finishes: If you plan on restoring from a Time Machine backup, you may have to create a new User and recover your old account logged in as the new one. If this does not work, you may have to manually reformat each drive, and proceed from step one.

Best Answer

Related Solutions

I think I messed up the Fusion Drive on the 1TB iMac (with BootCamp)

Restoring Fusion Drive after error on partition erase

Related Question