Re: GRUB2 not able to read ext4/xfs file systems on 8 TB drive

[Niklas Hambüchen]

Hi Pascal, thanks a lot for your answer.

> Is the firmware able to address 8 TB capacity ?

I am not quite sure how to find out.

> It has been reported that some BIOS firmwares cannot read sectors beyond 2 
> TiB.

Yes, indeed the server uses BIOS.

> You may test by switching from firmware disk drivers to GRUB native disk 
> drivers with the "nativedisks" commands. Be aware that drive names change and 
> (hdX) are not available any more, so any needed module must be loaded first.

Given that `nativedisk` is a module on the file system, and I cannot read the 
file system, I concluded that I'd have to bake the `nativedisk` module into the 
`core.img` module.

I did that by passing `"--modules=nativedisk pata"` to `grub-install`. Then I 
could run the command from the rescue mode:

    grub rescue> nativedisk
    error: file `/boot/grub/i386-pc/pata.mod' not found.

OK, so I extended to `"--modules=nativedisk pata"` to make `pata` available as 
well. However, when I boot that, I get:

    Native disk drivers are in use. Refusing to use firmware disk interface.
    error: disk 
`lvmid/DL6gaH-zwEE-DXgf-2sq0-pxTr-bXwP-0OvJxP/f5lkyV-NVXU-Kgsr-amDa-XkzF-66Iw-xtscXm'
 not found.
    Entering rescue mode...
    grub rescue>

So it seems that as soon as `pata` is available, it runs `nativedisk` by 
itself, without me having to type in the command?

As a result, GRUB2 now detects no devices at all:

    grub rescue> ls

Empty output.

Thus two questions:

1) Is it expected that `nativedisk` takes effect automatically?
2) How can I determine which modules I should add, and in which order?
   Can I somehow prompt GRUB2 to show me what it contains usually (in the 
rescue mode `lsmod` is not available)?

Thanks again,
Niklas