building LVM kernels for RH

[Net Llama!]

On Wed, 29 Jun 2005, James McDonald wrote:
> On Tue, Jun 28, 2005 at 05:08:28PM -0500, Net Llama! wrote:
> > Anyone here had any success building your own 2.6.x kernel from the
> > pristine kernel.org source on a RH system that is using LVM (either RHEL4
> > or FC3/4)?
> >
> > I've tried using an initrd and also compiling in support for LVM into the
> > 2.6.12.1 kernel, and both times, the root filesystem can't be found on
> > bootup:
> > VFS: Cannot open root device "mapper/VolGroup00-LogVol00" or
> > unknown-block(0,0)
> > Please append a correct "root=" boot option
> > Kernel panic - not syncing: VFS: Unable to mount root fs on
> > unknown-block(0,0)
> >
> > Surely there has to be a way to do this without using RH's kernel?
> >
>
> I think the LVM uses something called a device mapper to create
> "/dev/mapper/VolGroup00-LogVo100"

Right, that's what appears in both grub.conf and fstab, and also in df
output for the mount point's block device.

> Which I *think* is related to BLK_DEV_DM which needs to be enabled. I
> don't know what the config you are building from is like so this is a
> bit of a guess.

Yup, i had that enabled (tried both module & compiled in)

> I have found in the past that I had to set a physical path to the
> root=LABEL=/ option redhat uses. Perhaps try
> root="/dev/mapper/VolGroup00-LogVo100". But that was without an initrd.

That's what RH defaults to, and didn't work.
-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Lonni J Friedman                        netllama at linux-sxs.org
LlamaLand				http://netllama.linux-sxs.org