Arch Linux

Kaziuuu

Member

From: Opatów

Registered: 2023-06-27

Posts: 2

Trouble without nitrd/initramfs in kernel arch | LVM2,GRUB,EXT4,NVME

I recently started compiling my own kernel (based on arch), and I decided to delete initrd/initramfs from my kernel option.
   [ ] Initial RAM filesystem and RAM disk (initramfs/initrd) support

Unfortunately, I met many problems with booting process, and I decided to write that on topic for smartest people which maybe resolve that.
In arch wiki I didn't found any thread about compiling arch kernel without initrd/initramfs, then I decided to research information.
I read that instruction about compiling system without initial RAM, and carefully doing steps.
   https://firasuke.github.io/DOTSLASHLINU … initramfs/

It's good to mention, I'm using lvm2, ext4, nvme, grub.
   [.] The Extended 4 (ext4) filesystem
   <.> NVM Express block device
    [.] Multiple devices driver support (RAID and LVM)
    I turned off many things (a lot), like ATA, SCSI, etc...
    I am not using that devices in my computer.

If someone click in the link on top, will see fstab configuration. In this case I found first issue.
When everyone have disk like /dev/sda1... I have that:

NAME                                  MAJ:MIN RM   SIZE RO TYPE MOUNTPOINTS
nvme1n1                            259:0        0 476.9G       0 disk
|-vol_mapper-BACKUP    253:0        0    80G         0 lvm  /mnt/BACKUP
`-vol_mapper-FULL           253:1        0 429.3G      0 lvm  /mnt/FULL
nvme0n1                            259:1        0 232.9G      0 disk
|-nvme0n1p1                    259:2        0   512M      0 part
`-nvme0n1p2                     259:3        0 232.4G      0 part
  |-vol_mapper-FULL        253:1        0 429.3G      0 lvm  /mnt/FULL
  |-vol_mapper-SYSTEM  253:2         0    80G        0 lvm  /
  `-vol_mapper-USER        253:3         0   120G      0 lvm  /home

And big question, which one is correct? I think it's /dev/mapper/vol_mapper-SYSTEM, because it is root (/).
However I don't know that will works properly, because I don't have found any information about compatible with LVM2.

But, kernel such as xanmod, and normal linux can read fstab and boot.
  /dev/mapper/vol_mapper-SYSTEM         /               ext4            rw,relatime,stripe=32   0 1

I wrote grub like that:
  GRUB_CMDLINE_LINUX="root=/dev/mapper/vol_mapper-SYSTEM rootfstype=ext4 "

Later copy the bzImage, updated grub, and... only title: "booting linux" or something like that...
WHY? Because my computer has a USB mass storage device, and that was it. My usb blocked boot process.
After four hours of compiling kernel, I finally unplug USB mass storage device, and then...
Panic kernel... ); In nutshell: /dev/root: Can't open, go away! Seriously, root fs can't be mount. I have screenshots of error comunication.

Someone know what's went wrong?

Scimmia

Fellow

Registered: 2012-09-01

Posts: 13,726

Re: Trouble without nitrd/initramfs in kernel arch | LVM2,GRUB,EXT4,NVME

And how are you expecting to access the LVM without an initrd? The whole point of early userspace is to make the root filesystem available.