Ubuntu

Xubuntu fails to recognise root filesystem when booting, after sucessful install

Asked by Starry Steve

I have sucessfully installed Xubuntu v7.04 alternate(20070415), linux version 2.6.20-15, on an old Toshiba Satellite 300CDS laptop, but now it fails to mount the root filesystem when it boots from the hard disk.

The laptop is a P166 processor with 48Mb memory, a floppy, one 2Gb IDE HD, and a CD-ROM drive. It had Win95 installed, but I trashed that and created two partitions one for root and one for swap, on /dev/hda1, /dev/hda2 and /dev/hda5.

During install I had to add the following boot options: (acpi=off pci=biosirq ide=nodma) to get it to install sucessfully. I tried a few other options during boot, like: (irqpoll noapic nolapic apm=on idebus=66) but none of those seemed to help.

When I boot grub loads ok, I select recovery mode, and the install process gets all the way to where it trys to mount the root filesystem, and it waits for ages then it says:

(please excuse me, I had to type these out, I don't know how to capture the output otherwise)

Check root= bootarg cat /proc/cmdline
or missing modules, devices: cat /proc/modules ls /dev
ALERT! /edv/disk/by-uuid/(whole lot of numbers here...) does not exist. Dropping to a shell

and then comes up with a BusyBox prompt: "(initramfs)"

At this point /proc/cmdline contains:
root=UUID=(whole lot of numbers here...) ro single acpi=off pci=biosirq ide=nodma

/proc/modules contains an entry for floppy, usbcore, etc but nothing that looks like a hard disk

/dev/fd0 exists, but there is no /dev/hda1 or /dev/hda2 or /dev/hda5 or /dev/hdc (the CDROM) or any /dev/hd* at all.

I've looked back over the console log, and can't spot any errors of any kind.

I can boot from the alternate CD, select "rescue a broken system", select the HD root filesystem, it mounts the filesystem sucessfully, and I can look at the hard disk, but not sure why it can't boot from the hard disk alone. (I can provide contents of files if necessary, mounting a floppy works here)

I'm sorry, I don't know how to capture the console log for this question, I tried mounting a floppy in BusyBox, without success:
mdkir /floppy
mount -t vfat /dev/fd0 /floppy
mount: Mounting /dev/fd0 on /floppy failed: No such device

I've been working away at this for 3 days now, so any help or ideas would be appreciated!

Thanks!

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Anders Østerholt (diebels) said : 		#1

You need to put the correct UUID in /boot/grub/menu.lst

ls -l /dev/dev/disk/by-uuid/

and see which is pointing to hda1

I don't see how the installation got it wrong though...

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Starry Steve (stevem-xnet) said : 		#2

Thanks for the reply, Anders.

> ls -l /dev/dev/disk/by-uuid/
I assume you mean ls -l /dev/disk/by-uuid/ on the root file system on the hard disk? When I do an ls -l /dev/d* it can't find anything, also the /dev/hd* devices are not there either, it certainly can't mount them if they are not even in the directory in the first place. It's as if the disk is not detected at all ??

Regards,
- Steve

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Starry Steve (stevem-xnet) said : 		#3

Sorry, my mistake, the above should read:

When I do an ls -l /dev/d* it can't find anything, but the /dev/hd* devices are there.

Here's an idea: Can I use "e2label /dev/XXX <label>" to recreate the labels, or should I just create appropriate directories, as per the menu.lst, and create soft links with "ln -s" ?? I'll try that, and see if it works.

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Starry Steve (stevem-xnet) said : 		#4

Ok. I've just done a bit more research, and have found the following:

1) When the kernel fails to mount the root filesystem of the hard disk, and drops me into the (initramfs) prompt, there are no /dev/hd* devices present in the temporary filesystem at all. As far as I can tell, there is no way that the root filesystem is ever going to be mounted if the disk device doesn't exist in /dev (correct me if I'm wrong)

2) If I boot from the CD and select "rescue a broken system", I can mount /dev/hda1 and set it as my root filesystem no problems. When I was in there I noticed that there is a /dev/hda1 and NO /dev/disk/by-uuid, in fact no /dev/disk/* entries at all.

I then reinstalled GRUB, and the process created the appropriate uuid links in /dev/disk correctly (hurray!). I then tried to boot once more, and got the same old problem as in 1) above.

So, to me it looks like the HD is not being recognised by the kernel, even though GRUB has no problem recognising the disk device.

Help !!

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Markus Thielmann (thielmann) said : 		#5

A few additional questions:

1) When you're in the grub menu, which kernel (please be very specific) does grub offer you to start?
2) When at (initramfs) prompt, does /dev/sd* exist?

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Starry Steve (stevem-xnet) said : 		#6

Hi Markus, thanks for replying.

> 1) When you're in the grub menu, which kernel (please be very specific) does grub offer you to start?
When I attempt to boot from the hard disk, I hit ESC to get into grub, and there are three options in the list, the first one hightlighted, as follows:

Ununtu, kernel 2.6.20-15-generic
Ununtu, kernel 2.6.20-15-generic (recovery mode)
Ununtu, memtest86+

If I 'e'dit the first entry, I see:

root (hd0,0)
kernel /boot/vmlinuz-2.6.20-15-generic root=UID=(long uuid here) ro quiet acpi=off pci=biosirq ide=nodma idebus=66
initrd /boot/initrd.img-2.6.20-15-generic
quiet
savedefault

The second entry is:

root (hd0,0)
kernel /boot/vmlinuz-2.6.20-15-generic root=UID=(long uuid here) ro single
initrd /boot/initrd.img-2.6.20-15-generic

> 2) When at (initramfs) prompt, does /dev/sd* exist?
No. There are no hd* or sd* in /dev. When I do an fdisk -l (after booting from a Damn Small Linux CD) I get the following:

Disk /dev/hda 2167 MB

/dev/hda1 * Linux
/dev/hda2 Extended
/dev/hda5 Linux Swap

Thanks for your help!

Revision history for this message
Markus Thielmann (thielmann) said : 		#7

Allright, obviously you hit Bug #33269. It's reported for Dapper and Edgy, you might want to add Feisty to the list. You do so by selecting "Also affects distribution" and adding Ubuntu/linux-source-2.6.20.

Please don't forget to add a comment regarding your issues. It might a good idea to add all information you provided within this question.

Unfortunatly, it seems there's no solution for this until now. As the bug is rated "High" for dapper I'm quite sure someone will look into it. Please be prepared to provide additional information to the developers if they ask for it.

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Starry Steve (stevem-xnet) said : 		#8

Thanks Marcus, I've added a summary of these details to the bug as you suggested.

Regards,
- Steve

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Launchpad Janitor (janitor) said : 		#9

This question was expired because it remained in the 'Open' state without activity for the last 15 days.