No file system could mount root, tried: ext2 iso9660

ramachandra_ankireddy · 11-20-2008, 05:35 AM

I created a custom boot CD for RHEL 5 xen kernel (2.6.18-53.el5xen).
I created a customised initramfs image as gzipped compressed cpio image.
I am using isolinux boot loader. My isolinux.cfg looks like this.I am using the same kernel image that came with RHEL 5.

timeout 10
default 1
prompt 1

label 1
kernel mboot.c32
append xen.gz dom0_mem=256M mem=1G noacpi --- vmlinuz console=tty0 load_ramdisk=1 prompt_ramdisk=0 ramdisk_blocksize=1024 ramdisk_size=256M root=/dev/ram init=/linuxrc --- initrd.img noexec=off rw

I am trying to boot a VMWare guest with this boot cd image. It fails with the following error message.

No file system could mount root, tried: ext2 iso9660
kernel panic - not syncing : VFS: Unable to mount root fs on unknown- block(1,0).

I tried to use the initrd image that came with the RHEL 5 distribution. Looks like It works. I created the initrd image with the following command.
find . | cpio -o -c -H newc | gzip -9 > ../initramfs.igz

Can any one explain what could be the mistake in my approach.

jschiwal · 11-20-2008, 07:19 AM

Look for the intraramfs text file in the kernel source Documentation.

Quote:

The following shell script can create a prebuilt cpio archive you can
use in place of the above config file:

#!/bin/sh

# Copyright 2006 Rob Landley <rob@landley.net> and TimeSys Corporation.
# Licensed under GPL version 2

if [ $# -ne 2 ]
then
echo "usage: mkinitramfs directory imagename.cpio.gz"
exit 1
fi

if [ -d "$1" ]
then
echo "creating $2 from $1"
(cd "$1"; find . | cpio -o -H newc | gzip) > "$2"
else
echo "First argument must be a directory"
exit 1
fi

Note: The cpio man page contains some bad advice that will break your initramfs
archive if you follow it. It says "A typical way to generate the list
of filenames is with the find command; you should give find the -depth option
to minimize problems with permissions on directories that are unwritable or not
searchable." Don't do this when creating initramfs.cpio.gz images, it won't
work. The Linux kernel cpio extractor won't create files in a directory that
doesn't exist, so the directory entries must go before the files that go in
those directories. The above script gets them in the right order.