Arch Linux

agkbill

Member

Registered: 2011-06-13

Posts: 85

[SOLVED] Boot, failed to mount the real root device do not detect uuid

Hi all.

Having problems do get Arch to boot OK after installation.

When booting arch start to boot and then.

Waiting 10 seconds for /dev/disk/by-uuid/8516fa60-0d45-4f33-b269-817c5290f6cc
mount: mounting /dev/disk/by-uuid/8516fa60-0d45-4f33-b269-817c5290f6cc on /new_root failed: No such device
ERROR: Failed to mount the real root device.
Bailing out, you are on your own. Good luck.
[ramfs /]#

So it looks like the device is not find. But if I from the shell I am droped into do.

[ramfs /]#ls /dev/disk/by-uuid/

I can se 8516fa60-0d45-4f33-b269-817c5290f6cc

I have a multi boot system where GRUB2 in Kubuntu on /dev/sda is managing the boot.

Archlinux have its own disk, /dev/sdc with /boot on /dev/sdc1 uuid=8516fa60-0d45-4f33-b269-817c5290f6cc

Disk:

christer@Kubuntu:~/Documents$ ls -lF /dev/disk/by-uuid/
total 0
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 0088ABD388ABC60E -> ../../sdd1
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 07588b90-b464-4422-acbc-7c89e74eac6c -> ../../sdc2
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 2E3235B5323582BF -> ../../sdb2
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 3d093000-e27a-4722-9003-3b6c171cad0d -> ../../sda1
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 6df74e4d-6c13-444b-8c7d-d4231eb56d4a -> ../../sda4
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 8516fa60-0d45-4f33-b269-817c5290f6cc -> ../../sdc1
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 9f1d3309-b392-49f6-bc0b-4fce8caec8e0 -> ../../sda5
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 9f32e668-2548-4ed4-a10b-3fbea66a6d95 -> ../../sdc3
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 BC46C8EA46C8A70C -> ../../sdb1
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 c7a1174a-3bc2-48db-8d1b-fd910a25f6a6 -> ../../sdc4
lrwxrwxrwx 1 root root 10 2011-07-15 14:11 cece8b47-6d22-4038-81b6-7c65fb577810 -> ../../sda3
christer@Kubuntu:~/Documents$ blkid
/dev/sda1: UUID="3d093000-e27a-4722-9003-3b6c171cad0d" TYPE="ext2" 
/dev/sda3: UUID="cece8b47-6d22-4038-81b6-7c65fb577810" TYPE="ext4" 
/dev/sda4: LABEL="kubuntu_hd" UUID="6df74e4d-6c13-444b-8c7d-d4231eb56d4a" TYPE="ext4" 
/dev/sda5: UUID="9f1d3309-b392-49f6-bc0b-4fce8caec8e0" TYPE="swap" 
/dev/sdb1: LABEL="System Reserved" UUID="BC46C8EA46C8A70C" TYPE="ntfs" 
/dev/sdb2: LABEL="win7-hd" UUID="2E3235B5323582BF" TYPE="ntfs" 
/dev/sdc1: LABEL="arch-boot" UUID="8516fa60-0d45-4f33-b269-817c5290f6cc" TYPE="ext2" 
/dev/sdc2: UUID="07588b90-b464-4422-acbc-7c89e74eac6c" TYPE="swap" 
/dev/sdc3: LABEL="arch-root" UUID="9f32e668-2548-4ed4-a10b-3fbea66a6d95" SEC_TYPE="ext2" TYPE="ext3" 
/dev/sdc4: LABEL="arch-home" UUID="c7a1174a-3bc2-48db-8d1b-fd910a25f6a6" SEC_TYPE="ext2" TYPE="ext3" 
/dev/sdd1: LABEL="matrox" UUID="0088ABD388ABC60E" TYPE="ntfs" 
christer@Kubuntu:~/Documents$

To add Arch instalation to GRUB2 I have made a custom entry in /etc/grub.d/40_custom

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry "Arch Linux uuid"  {
        insmod part_msdos
        insmod ext2
        search --fs-uuid --no-floppy --set=root 8516fa60-0d45-4f33-b269-817c5290f6cc
        linux /vmlinuz26 root=/dev/disk/by-uuid/8516fa60-0d45-4f33-b269-817c5290f6cc ro vga=775
        initrd /kernel26.img
}

Any idea what I have missed here?

I noticed before that the disk I am using get assigned different device names by random, /dev/sda or /dev/sdc. That is way I am using uuid.

Thank you,

Best regards,
/Christer

PS: A bit of humour in the initial error message.

Last edited by agkbill (2011-07-15 16:01:24)

agkbill

Member

Registered: 2011-06-13

Posts: 85

Re: [SOLVED] Boot, failed to mount the real root device do not detect uuid

It was a very simple problem. I used the wrong uuid for my /

Correct entry in 40_custom is:

#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries.  Simply type the
# menu entries you want to add after this comment.  Be careful not to change
# the 'exec tail' line above.
menuentry "Arch Linux uuid"  {
        insmod part_msdos
        insmod ext2
        search --fs-uuid --no-floppy --set=root 8516fa60-0d45-4f33-b269-817c5290f6cc
        linux /vmlinuz26 root=/dev/disk/by-uuid/9f32e668-2548-4ed4-a10b-3fbea66a6d95 ro vga=775
        initrd /kernel26.img
}

Now the boot is working great. Next thing was that my /home and swap was not detected.

That was simply because /etc/fstab was still using /dev/sda etc naming. changing  that to uuid solved that part as well.

To use uuid all the way and of cause the correct one solved everything

/Christer

Last edited by agkbill (2011-07-15 16:00:30)