Re: question on how to (correctly) build an initrd for a root disk on a RAID1

[Luca Berra <bluca@comedia.it>]

On Sun, Oct 26, 2008 at 10:37:17PM -0400, Joe Landman wrote:
>Hi folks:
>
>  We have been trying to build an operational initrd for a root drive
>on  software RAID1.
>
>  Basic specs:   2.6.23.14 kernel (though same issues with 2.6.27.2
>kernel), on Centos 5.2, pair of SATA drives using libata and other
>drivers, x86_64 architecture.
Custom built kernel or centos provided kernel?


>  Using mkinitrd --with=raid1 --with=libata --with=sd_mod ...
>
>  I am getting a kernel panic on switchroot, it can't find the root
>file system.  I did some googling, but could not find a similar
>example.
unfortunately the kernel panic is a consequence of a previous error,
someone willing to help you would need to know everithing that was
spitted between the 'starting red-hat nash' message and the kernel
panic.

>Do I need to create a specialized init script?  Is there an
usually no, redhat/centos initrd should be able to boot from a raid1

>example of this somewhere?  I did look at the Documentation/md.txt and
>tried the
>
>     md=0,sda1,sdb1 md=1,sda2,sdb2  md=2,sda3,sdb3
if you are using the centos kernel, raid is modular and this parameter
has no effect.
mkinitrd should use your /etc/mdadm.conf to discover how the array
should be laid out.

>  kernel boot time option, to no avail.  Persistent superblocks are
>on, and the devices have the right partition types.
partition types do not matter anymore.

>
>  Any suggestions?  More things to read?
is your fstab correct?
is your mdadm.conf correct?
are you loading the correct drivers for your hd controller?

mkinitrd is a shell script, if all else fails, run it with sh -x and
read the output.

L.
-- 
Luca Berra -- bluca@comedia.it
         Communication Media & Services S.r.l.
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