Disk Utility reading disk incorrectly; viewing ext4 as JHFS+ and seeing Recovery HD

disk-utilityhard drivepartitionssdunix

This is imported from Superuser, I felt like I would have an easier time getting an answer here than in Superuser – it is copy pasted, as below.

So, I have some strange issues in Disk Utility and diskutil. It's not a problem (hopefully), but I just want to make sure that I'm not on the path to disk corruption or failure. This is how my disk utility reads my hard disk:

(as they are listed)

Disk Description : APPLE SSD SD0256F Media
Total Capacity : 251 GB (251,000,193,024 Bytes)
Connection Bus : PCI
Write Status : Read/Write
Type and Location : Solid State Disk, Internal
S.M.A.R.T. Status : Verified
Partition Map Scheme : GUID Partition Table

And here are the partitions:

Macintosh HD
- Format : Mac OS Extended (journaled)
- Size : 202.66 GB
Recovery HD
- Format : Mac OS Extended (journaled)
- Size : 650 MB
disk0s4
- Format : Mac OS Extended (journaled)
- Size : 46.8 GB
disk0s6
- Format : Linux Swap
- Size : 681.6 MB

The reason for my worry is two things: 1) Recovery HD is visible, which, I could be mistaken, but this shouldn't be visible OR mounted in Disk Utility, and 2) disk0s4 is actually ext4, NOT JHFS+.

Output from diskutil list:

    /dev/disk0
       #:                       TYPE NAME                    SIZE       IDENTIFIER
       0:      GUID_partition_scheme                        *251.0 GB   disk0
       1:                        EFI EFI                     209.7 MB   disk0s1
       2:                  Apple_HFS Macintosh HD            202.7 GB   disk0s2
       3:                  Apple_HFS Recovery HD             650.0 MB   disk0s3
       4: 0FC63DAF-8483-4772-8E79-3D69D8477DE4               46.8 GB    disk0s4
       5:                 Linux Swap                         681.6 MB   disk0s6

And from gdisk…

    >sudo gdisk /dev/disk0
    Password:
    GPT fdisk (gdisk) version 1.0.0

    Warning: Devices opened with shared lock will not have their
    partition table automatically reloaded!
    Partition table scan:
      MBR: hybrid
      BSD: not present
      APM: not present
      GPT: present

    Found valid GPT with hybrid MBR; using GPT.

    Command (? for help): p
    Disk /dev/disk0: 490234752 sectors, 233.8 GiB
    Logical sector size: 512 bytes
    Disk identifier (GUID): B01E51EA-D531-4CA4-ADA4-A936F8C27DCD
    Partition table holds up to 128 entries
    First usable sector is 34, last usable sector is 490234718
    Partitions will be aligned on 8-sector boundaries
    Total free space is 949 sectors (474.5 KiB)

    Number  Start (sector)    End (sector)  Size       Code  Name
       1              40          409639   200.0 MiB   EF00  EFI System Partition
       2          409640       396222607   188.7 GiB   AF00  Macintosh HD
       3       396222608       397492143   619.9 MiB   AF00  Recovery HD
       4       397492224       488902655   43.6 GiB    8300  
       6       488902656       490233855   650.0 MiB   8200  Apple_HFS_Untitled_2

    Command (? for help): ^C>

gpt has this output –

    >sudo gpt -vvv show /dev/disk0
    Password:
    gpt show: /dev/disk0: mediasize=251000193024; sectorsize=512; blocks=490234752
    gpt show: /dev/disk0: Suspicious MBR at sector 0
    gpt show: /dev/disk0: MBR part: type=175, start=409640, size=395812968
    gpt show: /dev/disk0: MBR part: type=175, start=396222608, size=1269536
    gpt show: /dev/disk0: MBR part: type=131, start=397492224, size=91410432
    gpt show: /dev/disk0: Pri GPT at sector 1
    gpt show: /dev/disk0: GPT partition: type=C12A7328-F81F-11D2-BA4B-00A0C93EC93B, start=40, size=409600
    gpt show: /dev/disk0: GPT partition: type=48465300-0000-11AA-AA11-00306543ECAC, start=409640, size=395812968
    gpt show: /dev/disk0: GPT partition: type=48465300-0000-11AA-AA11-00306543ECAC, start=396222608, size=1269536
    gpt show: /dev/disk0: GPT partition: type=0FC63DAF-8483-4772-8E79-3D69D8477DE4, start=397492224, size=91410432
    gpt show: /dev/disk0: GPT partition: type=0657FD6D-A4AB-43C4-84E5-0933C84B4F4F, start=488902656, size=1331200
    gpt show: /dev/disk0: Sec GPT at sector 490234751
          start       size  index  contents
              0          1         MBR
              1          1         Pri GPT header
              2         32         Pri GPT table
             34          6         
             40     409600      1  GPT part - C12A7328-F81F-11D2-BA4B-00A0C93EC93B
         409640  395812968      2  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
      396222608    1269536      3  GPT part - 48465300-0000-11AA-AA11-00306543ECAC
      397492144         80         
      397492224   91410432      4  GPT part - 0FC63DAF-8483-4772-8E79-3D69D8477DE4
      488902656    1331200      6  GPT part - 0657FD6D-A4AB-43C4-84E5-0933C84B4F4F
      490233856        863         
      490234719         32         Sec GPT table
      490234751          1         Sec GPT header

and fdisk…:

    >sudo fdisk /dev/disk0
    Disk: /dev/disk0    geometry: 30515/255/63 [490234752 sectors]
    Signature: 0xAA55
             Starting       Ending
     #: id  cyl  hd sec -  cyl  hd sec [     start -       size]
    ------------------------------------------------------------------------
     1: EE    0   0   1 - 1023 254  63 [         1 -     409639] <Unknown ID>
    *2: AF 1023 254  63 - 1023 254  63 [    409640 -  395812968] HFS+        
     3: AF 1023 254  63 - 1023 254  63 [ 396222608 -    1269536] HFS+        
     4: 83 1023 254  63 - 1023 254  63 [ 397492224 -   91410432] Linux files*

I have used gdisk before to make my hard drive hybridized MBR/GPT and have installed Ubuntu 14.04.

Anyone have an inkling to why this is, where is disk0s5, and will this be a problem?

Best Answer

If you want better answers, try refining your question. Also, post a comment after my answer, so I will be notified.

Question:

1) Recovery HD is visible, which, I could be mistaken, but this shouldn't be visible OR mounted in Disk Utility

Answer:

In the MBR partition table, the id should be AB and you have AF. In the GPT, the partition type should be 426F6F74-0000-11AA-AA11-00306543ECAC and you have48465300-0000-11AA-AA11-00306543ECAC. This is why it is visible.

Question:

2) disk0s4 is actually ext4, NOT JHFS+.

Answer:

You used the gdisk to change the partition type code for disk0s4 from AF00 to 8300 while disk0s4 while it was still mounted. The Disk Utility application will not see the change until you unmount and mount disk0s4.

Question:

where is disk0s5

Answer:

Currently, the fifth entry in the GPT is not being used. You have not given any information regarding the values in this table entry, other than due to its absence the partition type must be 00000000-0000-0000-0000-000000000000. For all anyone knows, the UUID, attributes, label and starting/ending sector numbers may still be stored in the fifth table entry.

Note: I have observed the Disk Utility application requires the entries in the GPT to be in ascending order and contiguous. The output of the gpt command shows the indices to be in ascending order, but since the fifth entry is missing, the indices are not contiguous. When a situation like this occurs, the Disk Utility application can incorrectly display the contents of the GPT. In your case, the errors shown by the Disk Utility application where most likely caused by the use of gdisk.

Why did you use a BIOS/MBR install of Ubuntu? I know you can download such an iso, but the EFI/GPT iso version also works on Mac's. This is what I choose for my mid 2007 20-inch iMac. This way you can avoid using a hybrid GPT.

Related Solutions

MacOS – Resetting MBR on iMac

Boot from an install DVD or USB key (If you have one).

From the first installer page choose Disk Utility from the Tools menu.

Check to see if it finds your partition.

Verify/Repair it.

Then, from Tools, choose Startup Disk, and see if you can set your system partition.

If you don't have an install DVD or USB key there are plenty of instructions around on how to do it.

iPartition can change partition schemes without wiping the disk if it comes to that. It's a great tool to have, I've used it a lot for various disk activities over the years, with Linux, Windows, and OSX partitions.

You need a GUID disk to boot OSX normally, not sure how you had it working with an MBR. Disk Utility will normally tell you what you have and how to correct it, if it can.

Long story short - make sure you back up your disk, you're probably going to be reformatting it.

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.

Best Answer

Related Solutions

MacOS – Resetting MBR on iMac

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

Related Question