[linux-lvm] LVM 1.03 root file system on Redhat 7.3

Thierry DE CARVALHO thierry.decarvalho at online.fr
Thu May 30 12:50:02 UTC 2002

"James B. Byrne" wrote:
> We are using the grub bootloader.  We have followed the
> instructions contained in the the lvm howto document provided by
> sistina, to the best of my ability to understand them.
> The problem is that system gives a kernel panic when started using
> the lvm boot option.  Is there a way to redirect the boot dialogue
> output to a file?  It appears that the most informative messages may
> be scrolling of the top of the screen.  What I am seeing is this:
> kmod: failed to exec /sbin/modeprobe -s -k block-major-7 errno = 2
> repeated 16 times, followed by
> vgvchange -- volume group "vg00" successfully activated
> VFS: Cannot open root device "vg00"/lv01: or 00:00
> Please append correct "root=" boot option
> Kernel panic: VFS: Unable to mount root fs on 00:00

The problem is that at this time the kernel don't known anything about
your LVs and their major/minor ! (the root FS is not mounted).
It uses an internal table for translating /dev/hda* and others to 
major/minor(see init/main.c).

Try with grub (here /dev/vg00/lvol1 is the root fs):

title=GNU/Linux Debian 2.2 (potato)
kernel (hd0,1)/vmlinuz-2.2.19 root=3a00 ramdisk_size=8192 vga=10
#                                   ^^^^ <major><minor> of the lv device in hex
initrd (hd0,1)/initrd-lvm-2.2.19.gz

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