Arch Linux

ealrann

Member

Registered: 2012-03-22

Posts: 11

Can't find root device /dev/disk/by-uuid/***

Hi !

After a pacman -Syu, I wasn't allow to reboot (Can't find root device /dev/disk/by-uuid/... ).

I tried a fresh core-install of Arch, same problem after the first pacman -Syu (and a net-install don't boot at all, same problem).

So I try a chroot (without forgetting to mount /boot), and i made a Syu and a :

 mkinitcpio -p linux 

no problem during the mkinitcpio, but it doesn't boot either.

If I try to reinstall linux package, mkinitcpio or udev (I don't try other), I have :

pacman -S udev
..
..
warning: could not get filesystem information for /bootmnt: No souch file or directory
warning: could not get filesystem information for /cowspace: No such file or directory
..
warning: could not get filesystem information for /bootmnt: No such file or directory

I don't know what to do :'(

Last edited by ealrann (2012-03-23 13:46:50)

Gcool

Member

Registered: 2011-08-16

Posts: 1,456

Re: Can't find root device /dev/disk/by-uuid/***

Double check if your bootloader config is actually pointing to the correct disk uuid and also verify that your mkinitcpio.conf contains the necessary modules.

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Burninate!

ealrann

Member

Registered: 2012-03-22

Posts: 11

Re: Can't find root device /dev/disk/by-uuid/***

Thanks for your answer

my menu.lst seems ok, and the uuid looks good (it is the same on /dev/disk/by-uidd/**)
But when I try booting whithout chroot, when I am on the emergency shell, there is no /dev/disk/by-uuid

For the mkinitcpio.conf, I don't know : it seems good too but ... I never had to change it to boot with this computer. On hooks I have :
HOOKS="base udev autodetect pata scsi sata filesystems usbinput fsck"

There is always files/directory missing when I try to pacman -S udev/linux/.... :

pacman -S udev
..
..
warning: could not get filesystem information for /bootmnt: No souch file or directory
warning: could not get filesystem information for /cowspace: No such file or directory
..

Oh, and I forgot to mention : I boot on a compact flash on IDE (but it was allways detected as a standard IDE HDD), and my CPU is an Atom D525.

kaptenen

Member

Registered: 2009-12-06

Posts: 287

Website

Re: Can't find root device /dev/disk/by-uuid/***

Same problem here... For me it complains about udevd and udevadm as well. Reinstall udev do not help.

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Blog

Gcool

Member

Registered: 2011-08-16

Posts: 1,456

Re: Can't find root device /dev/disk/by-uuid/***

Could you try if the issue still persists if you...

modprobe ahci
modprobe sd_mod

Or add both modules to the MODULES array in /etc/mkinitcpio.conf and regenerate your initramfs (mkinitcpio -p linux).

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Burninate!

PaulBx1

Member

Registered: 2008-10-18

Posts: 142

Re: Can't find root device /dev/disk/by-uuid/***

I have roughly the same problem. After having trouble, I reloaded my disk with a dd backup, booted it and did "pacman -Syu". Then rebooted and I get this:

Booting the kernel.
:: Starting udevd...
done.
:: Running Hook [udevd]
:: Triggering uevents...done.
Waiting 10 seconds for device /dev/mapper/cryptroot
ERROR: Unable to find root device '/dev/mapper/cryptroot'.

This is an Intel D510MO with a SSD using grub legacy and an old-fashioned MBR. Of course /boot is unencrypted and /, /home and /var are encrypted. LVM is not used.

It drops me to the shell. I don't know if this is normal or not, but 'ls' does not show me a /boot directory, nor do I see any evidence of the drive sda in mount or df.

<later>
Oh, now I realize that the only way it could know about "cryptroot" is if it read menu.lst, so the boot process must have got that far at least. Here is my kernel line in menu.lst:

kernel /vmlinuz-linux cryptdevice=/dev/sda2:cryptroot root=/dev/mapper/cryptroot ro

<later>
I reloaded from my backup and turned up the log messages, and captured a log of a successful boot. I then did "pacman -Syu" and rebooted. The logs are similar (that I can tell) up to the message about waiting for /dev/mapper/cryptroot. In the successful case the log reads instead:

Mar 26 08:58:10 localhost kernel: [    2.094172] device-mapper: uevent: version 1.0.3
Mar 26 08:58:10 localhost kernel: [    2.094597] device-mapper: ioctl: 4.22.0-ioctl (2011-10-19) initialised: dm-devel@redhat.com
Mar 26 08:58:10 localhost kernel: [   15.519705] Intel AES-NI instructions are not detected.
Mar 26 08:58:10 localhost kernel: [   15.953642] EXT4-fs (dm-0): mounted filesystem without journal. Opts: (null)
Mar 26 08:58:10 localhost [   16.668877] udevd[183]: starting version 181

Not sure this is the same as the OP or the other reports of non-booting since it seems to have to do with the mapper.

Guess I will leave this alone until a resolution comes along on the ubuntu kernel bug.

<later>
I found a note about not being able to find the root directory here:
https://wiki.archlinux.org/index.php/Pa … onger_boot.
I tried it (with extra steps for my encrypted system) but when I ran the pacman steps I got "error: failed to initialize alsp library..."
But maybe it will work for others.

Last edited by PaulBx1 (2012-03-26 19:04:40)

PaulBx1

Member

Registered: 2008-10-18

Posts: 142

Re: Can't find root device /dev/disk/by-uuid/***

OK, I think I figured it out for my case anyway.

I did not have "encrypt" in my hooks even though I found that note in the wiki about system encryption saying it was necessary. Well, that was wrong - at least before kernel 3.2.13 anyway. I suspect the boot process saw my kernel line in grub's menu.lst and deducted the "encrypt" hook was needed, and it said that as it booted too. But after upgrade to 3.2.13 it didn't work that way any more. It needs the "encrypt" hook explicitly. (I also added the "fsck" hook and "ext4" in the modules section since I am all ext4, but I doubt that affected it at all.)

Of course mkinitcpio must also be run:

# mkinitcpio -p linux

Then I rebooted to check that the newly generated files still booted, and they did. Then I finally did "pacman -Syu" for a full upgrade, and rebooted. And that worked too, so my problem is solved. Looks like this does not help the OP since he does not have encryption; sorry about that.