Arch Linux

gabx

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From: Geneva, Switzerland

Registered: 2011-11-20

Posts: 179

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[SOLVED]dual boot-Failed to mount real root device

Hello,

Here is my drives partition info:

/dev/sda1       2,949,122,048 3,907,028,991   957,906,944   7 NTFS / exFAT / HPFS
/dev/sda2               2,048   901,117,951   901,115,904  83 Linux
/dev/sda3    *    901,117,952 1,925,115,903 1,023,997,952   f W95 Extended (LBA)
/dev/sda5         901,120,000   901,439,487       319,488  83 Linux
/dev/sda6         901,441,536   905,648,127     4,206,592  82 Linux swap / Solaris
/dev/sda7         905,650,176 1,925,115,903 1,019,465,728  83 Linux
/dev/sda4       1,925,115,904 2,949,122,047 1,024,006,144   7 NTFS / exFAT / HPFS

/dev/sdb1               2,048     2,099,199     2,097,152  83 Linux
/dev/sdb2           2,099,200    53,299,199    51,200,000  83 Linux
/dev/sdb3          53,299,200    73,779,199    20,480,000  83 Linux
/dev/sdb4          73,779,200   224,673,791   150,894,592   7 NTFS / exFAT / HPFS

I installed Opensuse 12.1 on /dev/sda5. It is booting with Grub, working with no problems. The computer boots directly to Grub menu.

THEN, I installed Arch linux (last release) on both sda and sdb following these mounting points:

/dev/sdb1 mounted as /boot  Ext2
/dev/sdb2 mounted as /   BTRFS
/dev/sdb3 mounted as /usr  BTRFS
/dev/sda2 mounted as /home  BTRFS

Intstallation went smooth until the end. Installed the bootloader.

Now, I am trying to configure GRUB to boot Arch.

Here is what I added on /boot/grub/menu.lst, in sda5 under Opensuse:

title Arch Linux  [/boot/vmlinuz-linux]
    root (hd1,0)
    kernel /vmlinuz-linux root=/dev/sdb1 ro
    initrd /initramfs-linux.img

In Opensuse, i can check that vmlinux and grub/menu.lst are indeed in /dev/sdb1
My /etc/fstab is on /dev/sdb2

=============================== sdb2/etc/fstab: ==========

--------------------------------------------------------------------------------
#
# /etc/fstab: static file system information
#
# <file system>    <dir>    <type>    <options>    <dump>    <pass>
tmpfs        /tmp    tmpfs    nodev,nosuid    0    0
/dev/sda2 /home btrfs defaults 0 1
/dev/sdb1 /boot ext2 defaults 0 1
/dev/sdb2 / btrfs defaults 0 1
/dev/sdb3 /usr btrfs defaults 0 1
----------------------------------------------------------------------------------

With this parameters, i got an message error when booting Arch:

Mounting /dev/sdb1 on /new_root failed: no such device.
Error : failed to mount the real root device.

So, at busybox prompt, I tried this command line :

ramfs # mount -t ext2 /dev/sdb1

Got an error : Can't read /etc/fstab

I tried too to give a uuid adress to sdb1 in my menu.lst file, but it didn't change anything, so I am sure partition number is correct.

It seems to me in fact that GRUB can't find fstab.

Two questions :

-Would it be better in fact to use only 1 GRUB file for both systems? If yes, shall I keep only the grub config from Opensuse?
-What do I wrong with Arch booting? Why can't I boot Arch?

EDIT :1- just realised there is no BOOT flag in my partiton table on /dev/sdb.
            2- root is on /dev/sdb2, not sdb1.

1-I toggled my first partition bootable using fdisk
2-changed root to point to /dev/sdb2

Now booting into Arch login

Last edited by gabx (2011-11-22 22:33:09)