FC 13 Boot problem after update failure

[Steve4sport]

I was having problems performing an update yesterday that failed on dovecot dependancies and after a few tries I removed dovecote (it wasn't being used) from the installation and tried again. Everything seemed to be going OK then the update (about 160MB) hung and the screen went black a few times and I think then shutdown automatically.
The PC then fails to reboot and displayes the message
"Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)"

I have tried to get the PC to boot with the super grub disc but without success (probably my in experience)
I have also tried a suggestion from one of the forums to start the PC with a live CD and typed su -c 'grub-install /dev/sda at the terminal again without sucess.
I have looked at the files with the live CD there are grub, menu and kernel files there (some are in lost + found, b ut don't know wheer these should be so have not changed anything.


Is there an easy way for the in-experienced to repair the boot process ?

The PC is a pentium 4 running Fedora 13
There is a 200MB boot partition formated as Ext3
and a 19GB partition formated as a LVM with Ext4
There is a CD drive but no DVD

Everything has worked OK for the past year through two online upgrades.


Many thanks in anticipation

[Bender_Unit#21]

Last time i had that when somehow (probably the same failed upgrade of kernel as well) didn't create the initrd file. So if you didn't delete the old one then boot to it and resume the upgrade.

[Steve4sport]

Thanks for the reply

Any advice on how to boot to the the previous kernels? there are some vmlinuz and initrad files dated 23/7/2010 (ie prior to the update) in the lost and found folder, but with the live CD I don't seem to have permission to move these any where.

[Bender_Unit#21]

You lost the old ones from /boot partition ?

If your answer is affirmative then i see no other solution than to chroot to your install and install rpm's downloaded off the internet while in livecd:

Boot off the livecd

mkdir /mnt/fedora/
mount /dev/sdXx /mnt/fedora/ (where sdXx is your root partition)
mount /dev/sdYy /mnt/fedora/boot (where sdYy is your boot partition)
mount -t proc none /mnt/fedora/proc
mount -o bind /dev /mnt/fedora/dev
cp -L /etc/resolv.conf /mnt/fedora/etc/resolv.conf
chroot /mnt/fedora /bin/bash

You may try to update from there though i am not sure that the kernel will update properly, in that case try to copy livecd's /etc/mtab to your fedora installation's /etc/directory getting rid of unnecessary lines like livecd etc.

P.S. lost and found ey? filesystem got corrupted, didn't your PC hung in the middle of a kernel update ??
P.S.2 Didn't you just try to copy and not move the initrd images? Have you tried to modifygrub's menu.lst as to accomodate any initrd files left in /boot ?

[Donald Winslow]

You can use su -c 'cp {fill in source & destination files here}' to move the files while running the live cd. No root password is needed, but you still need the su command.

But first try to catch the boot menu by pressing the space bar after the manufacturer's logo has disappeared on startup. There should be lines to boot previous kernels there. If that doesn't work, you can take a look at /boot/grub/grub.conf from the livecd. You can comment out "hiddenmenu" so that the boot menu shows on startup.

[Steve4sport]

Blender

Thanks for the reply, unfortunately this seems to be turning into a nightmare through just not knowing what I am doing and wondering if just reinstalling is the easier/quicker option.

re your questions
You lost the old ones from /boot partition ?
what are you refering to "the old ones"?

I don't then understand your process and what it is trying to achieve, since I'm not bothered about the update but just want to be able to boot into the system. If I can do that, can I not jsut start the update process again in the normal manner?

re your PS
yes the PC hung in the middle of an update, what is the significance?

re your PS2
yes I tried to copy the initrad and kernels but didn't have the necessary permission using the live cd (with dolphin),
there are no initrd files left in boot.
I did try to modify menu.1st (by opening in dolphin) but it was an unknown file type (size only 1.4k) and gedit was not able to open.
similarly grub.conf was an unknown file type size only 1.4k again.


I remembered from using SUSE a while back that the DVD rescue mode allowed one to go through the installation elements and check they were OK and thus review and amend grub via the GUI, can this not be done in Fedora?
I have just downloaded the 1st CD which seems to have the resue menu but the interface is very / very basic and didnt really help. Is there nothing similar to SUSE in Fedora?


Donald

Re the PS2 notes above, how do I get to see (or reinstall) the menu.1st or grub.conf files, there is something there (possibly) but i cannot see what it is

[Bender_Unit#21]

Hmm, i assumed you know a little on how to use linux.

Generally when you update kernel for example then the old one is still kept in /boot partition in case the new one breaks something.

If you have /home on a separate partition then go ahead and reinstall

Well, my instructions were given to "boot" the system from within the livecd. So that you could actually fix it and boot it after restart. I reinstall only as a last resort thought it is sometimes faster than recovering

If the update is interrupted at some stage it may leave your system broken or the system may behave very unstable after that.

[Donald Winslow]

First, let me call attention to a suggestion I made at the end of my last comment. If the old kernels are still in /boot, it should be easy to boot one of them simply by going into the grub boot menu on startup. This menu is normally hidden to facilitate a quick boot, but you can catch the menu by pressing the space bar after the manufacturer's logo disappears just after you power the machine on.

If the old kernels (vmlinuz files) and initramfs files are no longer in /boot, then you may try to copy them from somewhere else. However, you will not be able to do that with Dolphin or any other graphical file manager. This is because you have to be a root user to modify system files, and Fedora does not allow graphical programs to be opened as root (for security reasons). Instead you need to open a terminal from the Live CD and type some commands.

The first command to enter would be:

ls /media

The output should list the names for your partitions as the LiveCD sees them. One of those will be the boot partition. You can check the contents of each partition with "ls/media/PARTITIONNAME".
(Insert the partition name from the output of the last command where I have written "PARTITIONNAME".)
The boot partition will be the one that contains the vmlinuz and initramfs files and a /grub subdirectory. Check to see whether the old kernels(vmlinuz) and matching initramfs files are there. If they are there, you can modify /boot/grub/grub.conf or /boot/grub/menu.lst to make sure the old kernels will boot (see below) and also type "#" in front of "hiddenmenu" so that the boot menu will show on startup.

In order to enter commands as root, you need to use sudo. The simplest thing to do is to type "su" and hit enter; then you will be in a root shell, and any command you type will work regardless of permissions. I like to do things the hard way, so I usually use "su -c" with the command following in quotes. For instance, to use the copy command you can type:

su -c 'cp /boot/vmlinuz* /media/PARTITIONNAME/'

Note that in this command you are copying files from the LIveCD's boot directory to the boot partition. Copy the initramfs files in a similar manner. You also need to modify /boot/grub/grub.conf or /boot/grub/menu.lst (Note that's an "l" and not a "1" in menu.lst). menu.lst is a link to grub.conf, so modifying either one of them will work. You can do that with:

su -c 'gedit /media/PARTITIONNAME/grub/menu.lst'

When gedit opens the file, make sure that there is an entry for each kernel (vmlinuz + initramfs) you copied over. If not, you can copy and paste from the menu.lst file in the /boot directory on the LiveCD.

Hope this helps!

Donald

[Steve4sport]

Thanks Donald

I didnt understand the space bar at first but on second reading it got me back into the system all be it with an earlier Kernel

I believe the update recommenced automatically on reboot but stopped with conflicts.

On reading a number of other posts I did

yum update but that did not make any difference so after reading more posts did

yum clean all
yum update but again that did not make any difference.

yum update seems to be telling me it has resolved all the dependancies, then downloaded all (194) packages and then performed a Transaction Test returning an error.

file /usr/share/qt4/translations/assistant_adp_de from install of qt-x11-1:4.6.3-8.fc13.i686 conflicts with file from package qt-1:4.6.2-20.fc13i686

There are a total of 26 conflicts all to do with different translation files but the same packages.

Do you have any advise to resolve this?


Just one other small point I # ed out the hidden line in the menu.lst file and rebooted the PC but the option screen did not appear, I had to reboot again using the space bar and on checking the menu.ist file noted that the #hidden change was saved OK, any pointers?


Thanks very much for your help to date



Blender

Sorry I believe I may have mislead you with the location of the boot files.
Thanks for your assitance, I am begining to see there is a lot going on in the terminal that I need to understand, Is there any where to read or did you pick it up by trial and error.?

[Donald Winslow]

You can run "yum update --skip-broken" to update everything that doesn't have a dependency conflict. For the depsolving problems, it is possible sometimes to uninstall newer versions of packages, install the updates, and then try to reinstall the ones you took off. You can use "yum erase" or "yum downgrade" for this. See the yum manual at "man yum".

The other thing I forgot to mention about the grub configuration is that you have to change the timeout value in /boot/grub/menu.lst. I believe the default is timeout=0, meaning the menu will show for 0 seconds. I have mine set at timeout=5.

I believe the Free Software Foundation has published a new introduction to the command line, but I haven't seen it. Otherwise, you can pick it up from forums like this or by reading the man pages.

[Steve4sport]

MANY THANKS DONALD

I appear to have a working system again and have learnt something in the process.

Your help was much appreciated.