Re: grub2 - add NVME to boot from - how?

[Pascal Hambourg]

Le 07/03/2019 à 20:26, lejeczek a écrit :
> On 16/08/2018 19:38, Pascal Hambourg wrote:
> > If the motherboard has an M.2 slot, it is unlikely that the firmware
> > does not have support for NVME. Note however that some UEFI firmwares
> > may support NVME only with EFI boot, not with BIOS/legacy boot.
>
> I have an oldish box which is has no NVMe support, not in form of M.2
> slot, but I got that cheap PCIe M.2 adapter.

Does the adapter card have a BIOS ROM extension adding NVMe support ?

> Now, I have done dd my original whole drive to NVMe, then I dd my
> original drive to another small SSD, fdisk it so only boot partition
> remains on this "new" SSD.
>
> Something is obviously missing there in this simplistic approach,
> although kernel boots from this new small SSD it does not load the rest
> of the whole system.
>
> I am stuck with dracut.
>
> That would be grub or/and dracut need tweaking?

The kernel and initramfs are running, so GRUB did its job.

I do not know dracut at all, using only Debians's default initramfs 
generator initramfs-tools.

How is the root filesystem specified ? With the root= parameter in the 
kernel line (passed by GRUB) or embedded into the initramfs ? By UUID or 
device name /dev/something ? SATA devices have /dev/sd* names, NVMe 
devices have /dev/nvme* names.

Some initramfs generators include only the drivers needed to mount the 
root filesystem, others include more generic support (may be 
configurable). Is NVMe support included in the current initramfs ?

Does Dracut's initramfs include a debug/rescue mode with a shell 
allowing to investigate ?