Boot Camp Assistant

Run partitioning in 'normal' boot mode, and do not specify any specific physical storage during partitioning. Let APFS pick the destination. The SATA secondary should not have a 'minimum' of 999GB.

Also, when booted normally, post the output of

diskutil apfs resizeContainer disk0s2 limits

diskutil apfs resizeContainer disk1s2 limits

This will be tricky. Notice the Solid State flag is 'Yes' for both devices. BC Assistant does not know what to do. 2015 Macs do not support USB installers. As a test, can you create a FAT partition in Disk Utility and check. The partition should be cerated on the 1TB SATA SSD.

If APFS is unhappy with the secondary slice being smaller than the primary disk slice, because we pre-partitioned the disks, there is a workaround.

The following command...

 diskutil apfs resizeContainer 

Usage:  diskutil APFS resizeContainer <inputDisk> limits [-plist]

        diskutil APFS resizeContainer <inputDisk> <newSize> [<triple>*]

        where <inputDisk> = A Container Reference DiskIdentifier (preferred)

              or a Physical Store DiskIdentifier

              <newSize> = the desired new Container or Physical Store size

              <triple> = a { fileSystemPersonality, name, size } tuple

allows a physical disk store.

• We can recreate the APFS fusion with the PCIe as main, SATA as secondary when the disks do not have a Windows partition.
• Then we can resizeContainer and use the SATA disk (currently disk1 in your output) as the <inputDisk> parameter.
  • The 'tuple' would be 'exFat BOOTCAMP 0'
  • The <newSize> would be 1.5tb,
  • which would give you a ~499GB BOOTCAMP exFat partition.
• You should test IO speeds, before you install Windows.

eSolorio wrote:

Hi Loner T,

Did you by chance get a second to read all the updates since your last response? Just wondering if you had some thoughts on where I went wrong?

Without seeing the error messages in step 3 and later, it may be guesswork.

So in reference to what you just mentioned, I did create a container with both SSD drives w/out the windows partition (checked IO speeds as well to verify it was using PCIe as the main, and it checked out), then tried to resizeContainer to 1.5t using the command function you just mentioned and I ran into the same error that the container could not be resized bc it needed all of the space (it looked just like the error when we did resetFusion).

Perhaps I wrote the command wrong?

Is this what I should write, diskutil apfs resizeContainer disk1 1.5t exFat BOOTCAMP 0 ???

Can you post the output, if you still have it?

as I mentioned I currently have it set up w the PCIe as -main, and the Windows partition on the PCIe as well. Im assuming you dont want me using BCA to try to install Windows since we created the bootable USB? Are there different steps to take when installing Windows that I might be missing?

BCA will cause the same issue again.

Lastly, can I try to install windows w current setup or does the partition NEED to be on the SATA drive?

There is no requirement for Windows to be on SATA disk. The two factors that are the root cause of your issues are

• two SSDs, which APFS is not a good design for.
• two SSDs of the same size, which causes APFS to fail. It is a poor engineering choice on Apple's part, but it is a justifiable design.

APFS Fusion assumes that one disk is slower and larger than another. CoreStorage Fusion is a much better design. APFS implementation is a poor replacement.

I personally have made a choice to not use APFS Fusion at all. I still use CS Fusion on Sierra.

Can you post the output of

diskutil list

diskutil apfs list

BC Assistant also sets up parameters, helps hide the Fusion aspects of the two underlying disks. Instead of the USB, we can test the OSXRESERVED method. This would require creating another 10GB partition, and copying the contents of the USB to this 10GB partition and booting from it. It may not work, but is worth a test.

Can you post the output of

diskutil list

diskutil apfs list

and note which one is SATA and which one is PCIe.

If you have the Windows partition, but no working Windows, when you boot from the USB, are you allowed to choose and install Windows on that partition? If you attempt it, can you take photos of errors and then we can take a look. We can also manually create a OSXRESERVED partition, if the USB causes issues.