Boot problem after kernel upgrade while external USB drive connected - help, please!

[jaimito]

:: Resolved ::

This is a very silly issue, but I'm posting for two reasons:

1. As a warning - don't do this!
2. To request help to resolve the issue as I am stuck.

There was a recent 32-4 kernel upgrade released.

As I had a machine on the bench at the time, I ran the upgrade and all was fine, no issues whatsoever.

*However* I had an external USB drive plugged in (and manually mounted under /media/usbdisk) for temporary backups at the time.

Once I unplugged the (now unmounted) USB drive the system would not reboot.

I have gone through every detail of /grub/device.map and /grub/menu.list including rebuilding grub without the USB drive plugged in - several times!

I can see no error in this - but it still will not boot without the USB drive being plugged in!

Immediately after the upgrade the device.map DID have the USB drive as hd0 but I corrected this, makes no difference.

I can easily rebuild the machine, but I want to know what has happened and why.

The machine is an HP server, 410i hardware RAID with two arrays:

- proxmox on the first, /dev/cciss/c0d0

This has two partitions (allcreated by proxmox) /dev/cciss/c0d0p1 (boot) and p2

- and the second as an LVM with VM's on it, no partitions: /dev/cciss/c0d1.

What have I missed?

Here's the current contents of the relevant files: I have tried various permutations, but when I run rebuild-grub or grub-install it sets them back to the same defaults.

fstab:

# <file system> <mount point> <type> <options> <dump> <pass>
/dev/pve/root / ext3 errors=remount-ro 0 1
/dev/pve/data /var/lib/vz ext3 defaults 0 1
UUID=9502d516-8caf-47f0-906e-74e9cf1e2f8b /boot ext3 defaults 0 1
/dev/pve/swap none swap sw 0 0
proc /proc proc defaults 0 0

/grub/device.map:

(hd0)   /dev/cciss/c0d0
(hd1)   /dev/cciss/c0d1

/grub/menu.list:

# menu.lst - See: grub(8), info grub, update-grub(8)
#            grub-install(8), grub-floppy(8),
#            grub-md5-crypt, /usr/share/doc/grub
#            and /usr/share/doc/grub-legacy-doc/.

## default num
# Set the default entry to the entry number NUM. Numbering starts from 0, and
# the entry number 0 is the default if the command is not used.
#
# You can specify 'saved' instead of a number. In this case, the default entry
# is the entry saved with the command 'savedefault'.
# WARNING: If you are using dmraid do not change this entry to 'saved' or your
# array will desync and will not let you boot your system.
default         0

## timeout sec
# Set a timeout, in SEC seconds, before automatically booting the default entry
# (normally the first entry defined).
timeout         5

# Pretty colours
color cyan/blue white/blue

## password ['--md5'] passwd
# If used in the first section of a menu file, disable all interactive editing
# control (menu entry editor and command-line)  and entries protected by the
# command 'lock'
# e.g. password topsecret
#      password --md5 $1$gLhU0/$aW78kHK1QfV3P2b2znUoe/
# password topsecret

#
# examples
#
# title         Windows 95/98/NT/2000
# root          (hd0,0)
# makeactive
# chainloader   +1
#
# title         Linux
# root          (hd0,1)
# kernel        /vmlinuz root=/dev/hda2 ro
#

#
# Put static boot stanzas before and/or after AUTOMAGIC KERNEL LIST

### BEGIN AUTOMAGIC KERNELS LIST
## lines between the AUTOMAGIC KERNELS LIST markers will be modified
## by the debian update-grub script except for the default options below

## DO NOT UNCOMMENT THEM, Just edit them to your needs

## ## Start Default Options ##
## default kernel options
## default kernel options for automagic boot options
## If you want special options for specific kernels use kopt_x_y_z
## where x.y.z is kernel version. Minor versions can be omitted.
## e.g. kopt=root=/dev/hda1 ro
##      kopt_2_6_8=root=/dev/hdc1 ro
##      kopt_2_6_8_2_686=root=/dev/hdc2 ro
# kopt=root=/dev/mapper/pve-root ro

## default grub root device
## e.g. groot=(hd0,0)
# groot=(hd0,0)

## should update-grub create alternative automagic boot options
## e.g. alternative=true
##      alternative=false
# alternative=false

## should update-grub lock alternative automagic boot options
## e.g. lockalternative=true
##      lockalternative=false
# lockalternative=false

## additional options to use with the default boot option, but not with the
## alternatives
## e.g. defoptions=vga=791 resume=/dev/hda5
# defoptions=
## should update-grub lock old automagic boot options
## e.g. lockold=false
##      lockold=true
# lockold=false

## Xen hypervisor options to use with the default Xen boot option
# xenhopt=

## Xen Linux kernel options to use with the default Xen boot option
# xenkopt=console=tty0

## altoption boot targets option
## multiple altoptions lines are allowed
## e.g. altoptions=(extra menu suffix) extra boot options
##      altoptions=(single-user) single
# altoptions=(single-user mode) single

## controls how many kernels should be put into the menu.lst
## only counts the first occurence of a kernel, not the
## alternative kernel options
## e.g. howmany=all
##      howmany=7
# howmany=all

## should update-grub create memtest86 boot option
## e.g. memtest86=true
##      memtest86=false
# memtest86=true

## should update-grub adjust the value of the default booted system
## can be true or false
# updatedefaultentry=false

## should update-grub add savedefault to the default options
## can be true or false
# savedefault=false

## ## End Default Options ##
title           Proxmox Virtual Environment, kernel 2.6.32-4-pve
root            (hd1,0)
kernel          /vmlinuz-2.6.32-4-pve root=/dev/mapper/pve-root ro
initrd          /initrd.img-2.6.32-4-pve

title           Proxmox Virtual Environment, kernel 2.6.32-3-pve
root            (hd1,0)
kernel          /vmlinuz-2.6.32-3-pve root=/dev/mapper/pve-root ro
initrd          /initrd.img-2.6.32-3-pve

title           Proxmox Virtual Environment, kernel memtest86+
root            (hd1,0)
kernel          /memtest86+.bin

### END DEBIAN AUTOMAGIC KERNELS LIST

 

[macday]

Re: Boot problem after kernel upgrade while external USB drive connected - help, plea

Hi,

I had the same issue. I think your MBR is on the USB-Drive or somewhere else.

 

[jaimito]

Re: Boot problem after kernel upgrade while external USB drive connected - help, plea

Duh! Of course! Yes you were quite right, it had written the MBR to the wrong drive. What I had overlooked is the Grub trashes the original MBR in this case...

Thank you!