Grub2, chroot on mdadm RAID 1

Post by **^rooker** » Thu Feb 02, 2017 9:06 pm

Trying to install GRUB on 2TB harddisks, GPT with software RAID 1...

grub-install in chroot of mounted md127 throws error:

grub-install /dev/sda
/usr/sbin/grub-probe: error: no such disk.
Auto-detection of a filesystem of /dev/md127 failed.

I had to install "mdadm" on the target (chroot) system.
Next error:

$ grub-probe -d /dev/md127

Returned:

grub-probe: error: no such disk.

Changed to metadata version of the mdadm RAID to 0.90.

Had to add "--recheck". Then it worked:

$ grub-install --recheck /dev/sda"

Uncomfortable.

Links:

Post by **^rooker** » Mon Jul 10, 2017 3:29 pm

Workaround for initial boot (OS root on first partition of "md/0") - with mdadm metadata version 1.2 (!)

ls
ls (md/0,msdos1)/
set root=(md/0,msdos1)
ls /
set prefix=(md/0,msdos1)/boot/grub
insmod mdraid
insmod linux
normal

Post by **^rooker** » Mon Jul 10, 2017 6:29 pm

The above notes seem to be incomplete. At least, the didn't work like that the 2nd time I ran into the same problem.

Here are new notes:

target system =Debian 6 (Squeeze)
Partition the disks for target system:
20GB (filetype "fd" = Linux raid autodetect)
Leave rest unpartitioned. Starting at sector 2048 (1TB disks)
Create the mdadm RAID1 for the target system:
mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/sda1 /dev/sdb1
20 GB (ext4) (5% reserved for root)
mount target system (Debian Squeeze) on Live distro (Ubuntu 14.04)
mount sys,proc,dev on target system:
mount -o bind /sys <target>/sys
mount -o bind /proc <target>/proc
mount -o bind /dev <target>/dev
chroot to the target system

On the chrooted target system:

Das Werkstatt