On macOS the disk size is wrong

[Migulon]

It's doubled. Strange. For block storage.

[rareinator]

So I know this is a kinda old issue but just ran into this issue as well. Looks to be because of the way diskutil reads the drives from MacOS.
When I run the diskutil list i get 3 total drives, one being marked as (internal, physical). Which seems to be the right one, and then a second one marked (synthesized), which seems to be something that occurs because of the APFS filesystem.
It was introduced in macOS 10.12.4

Here is the output

/dev/disk0 (internal, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *500.3 GB   disk0
   1:                        EFI ⁨EFI⁩                     314.6 MB   disk0s1
   2:                 Apple_APFS ⁨Container disk1⁩         500.0 GB   disk0s2

/dev/disk1 (synthesized):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      APFS Container Scheme -                      +500.0 GB   disk1
                                 Physical Store disk0s2
   1:                APFS Volume ⁨Macintosh HD - Data⁩     458.4 GB   disk1s1
   2:                APFS Volume ⁨Preboot⁩                 476.1 MB   disk1s2
   3:                APFS Volume ⁨Recovery⁩                1.1 GB     disk1s3
   4:                APFS Volume ⁨VM⁩                      3.2 GB     disk1s4
   5:                APFS Volume ⁨Macintosh HD⁩            15.7 GB    disk1s5
   6:              APFS Snapshot ⁨com.apple.os.update-...⁩ 15.7 GB    disk1s5s1

/dev/disk2 (disk image):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        +838.9 MB   disk2
   1:                  Apple_HFS ⁨FontForge⁩               838.8 MB   disk2s1

I will try and look into if its possible to see from diskutil list -plist which one is the right one

[jaypipes]

Hi @rareinator and @Migulon! sorry for the delay in looking into this, and thank you @rareinator for providing some hints as to why this is happening on MacOS. I don't have a Mac handy at this point to experiment with, unfortunately, which is part of the reason why Mac support in ghw is so much behind Linux and Windows.

[rareinator]

Hi, @jaypipes yeah no worries 😃 I looked into it a bit last night and from what I could gather it seems that the -plist option returns the APFS scheme with a key called APFSPhysicalStores.
If you need anything else from me you can always reach out, I can also upload the entire output on Pastebin or something😃