Boot Problem after Crash

[Lennart Sorensen]

On Fri, Mar 07, 2008 at 04:56:21PM -0400, Tony Abou-Assaleh wrote:
> Lennart Sorensen wrote:
> >On Fri, Mar 07, 2008 at 01:39:18PM -0400, Tony Abou-Assaleh wrote:
> >>Hi tlugers,
> >>
> >>My PSU was toasted. I took the HDD out and installed it on another PC. 
> >>The file system had problems but after e2fsck it appears stable. No data 
> >>was lost as far as I can tell, but I couldn't boot into by Ubuntu 7.10 
> >>(xubunutu) Linux.
> >>
> >>I booted using a live CD and went to rescue mode. I updated/upgraded 
> >>packages using apt-get, executed update-initramfs, and all seemed well. 
> >>I can even start apache and sshd from this rescue shell.
> >>
> >>When I try to boot from the HDD I consistently get the same thing: I get 
> >>the BusyBox initramfs shell and I don't know how to go past that. 
> >>Nothing is mounted.
> >>
> >>I have the boot partition on /dev/sda1 and the root partition on raid1 
> >>volume. I am using only a single drive from the raid array.
> >>
> >>Any ideas why I'm getting the initramfs prompt on boot and how to get 
> >>past that?
> >
> >Perhaps the new machine enumerates the disks differently so it doesn't
> >know where to look for the root.
> >
> >What do you get from 'cat /proc/partitions' in the initramfs shell?
> 
> --
> major	minor	#blocks	name
> 8	0	xxx	sda
> 8	1	xxx	sda1
> 8	2	xxx	sda2
> 9	0	xxx	md0
> --
> 
> I omitted the block counts. sda1 is the boot partition, and sda2 is the 
> raid container. When I run the same command from the recovery shell, I 
> get 2 additional entries:
> 
> --
> 253	0	xxx	dm-0
> 253	1	xxx	dm-1
> --
> 
> Where dm-0 is the swap partition and dm-1 is the root partition.
> 
> >How about /proc/mdstat?
> 
> --
> Personalities : [raid1]
> md0 : active raid1 sda2[0]
> 	xxx blocks [2/1] [U_]

So one disk in the raid failed to appear?

> unused devices: <none>
> --
> 
> >Perhaps you can find out what root is called and change the boot loader
> >to use root= whatever that is.
> >
> >I do everything in the boot loader and fstab by UUID these days just to
> >avoid this kind of hassle.
> 
> I changed it to use root=UUID=xxx in the grub menu.lst, same thing.

Can you mount the root partitions from initramfs and then pivotroot or
whatever they call it now to it and continue the boot?

> >The other option is that your initramfs only loaded the driver modules
> >needed by the old machine and not the ones for the new one, although
> >most I have seen recently (in debian at least) try to load pretty much
> >everything.  Is the new machine perhaps too new or simply not supported
> >by your linux version?
> 
> I can boot fine from a live CD, so the machine is linux compatible. I 
> was able to connect to the Internet, start apache and sshd manually, and 
> connect to them from another machine.
> 
> Also I ran update-initramfs on the new machine, so again that's not 
> likely to be the problem.
> 
> It looks like the raid volume is recognized during the boot sequence, 
> but the partitions within it are not. Any ideas?

I have never used partitions on raid.  I always run LVM on raid.  I know
how that works.  LVM is much more flexible than partitions, so why use
partitions on raid?

--
Len Sorensen
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