Re: Problem booting RAID1/mdadm system when one disk is unplugged

[Scott Gifford <sgifford@suspectclass.com>]

James Brown <jbrown@orange.net> writes:

[...]

> I was advised this was a problem with my initrd because it didn't
> contain a mdadm.conf file and presumably that I should
>
> Unfortunately, some friends of mine do not agree that my initrd is the
> problem because they point out that I can still boot when two disks
> are present. What do people here think?

I had a somewhat similar problem, the cause of which turned out to be
that I didn't have /dev/md* in my initrd.  Building a new initrd with
mkinitrd fixed the problem.  You can mount your initrd images as
filesystems to quickly see what's in them, by using the "cramfs"
filesystem type and the "loop" option:

    mkdir -p /mnt/initrd
    mount -o loop -t cramfs /path/to/initrd.img  /mnt/initrd

I also found these guides very useful for setting up RAID with grub:

    http://www.linuxsa.org.au/mailing-list/2003-07/1270.html
    http://www.debian-administration.org/articles/238

----Scott.