Hi.

I'm trying to boot on an EFI based system with the help of initramfs and grub2, where the root partition is on an LVM volume located on sdb.

So the problem is, that although the system finds and starts GRUB fine; GRUB finds and starts initramfs located also on the LVM volume just fine; the initramfs itself does not find the root partition on its own.

First, it was trying to find root on sda2, but I added a line in genkernel.conf to supply initramfs the proper location of root (REAL_ROOT=/dev/mapper/vg0-lvol1). Now it is looking at the proper location, but it fails to locate it as it doesn't seem to exist. By dropping to the emergency shell, blkid instantly reveals that the logical volumes indeed do not seem to exist. By manually activating the log. volumes (lvm vgchange -a y vg0) and then running blkid again reveals that all logical volumes are now activated, thus this proves that initramfs indeed has lvm capabilities, it just fails to activate them automatically.

Thus the question is: how to make a genkernel generated initramfs automatically activate my logical volumes, so that the system could finally boot properly?

FYI: I indeed added "dolvm" to the grub kernel paramters for boot, but it seems it has little effect, as until I didn't provide the REAL_ROOT paramter into the genkernel.conf itself, the initramfs was never looking for root in the right place (even with grub real_root parameters).

I'm trying to use gentoo stable.

The sdb1 vfat (boot) partition was mounted to /boot/efi

/boot (on lvol1) contains all grub config and files, but the grub folder of sdb1 is empty (is it bad?)

Thanks in advance.

Is CONFIG_BLK_DEV_DM=y in the kernel or is the module loaded in the initramfs?

Hi.
Yes, it is in the kernel.

You can look in the initrd and see if the scripts contain the instructions to access the LVM volume. The initrd is a compressed cpio archive. You can unpack it by going to a temporary directory and runningDoes the file scripts/local-top/lvm2 even exist? It probably won't if the initrd was built while you were not using LVM.

The kernel parameter dolvm activates the LVM part only if it is present in the iniitrd. Did you tell genkernel to actually include LVM functionality in the initrd using the --lvm option?

Of course. I edited the genkernel.conf and modified/uncommented the line to: LVM="yes".
I don't think we are dealing with a missing capabilty, as the activation of lvm volumes works, if done manually in the emergency shell included in initramfs. My only problem is, that the initramfs doesn't do it automatically.