Bug#526525: a problem with mptbase or bnx2 (was: Bug#526525: Kernel linux-image-2.6.26-2-amd64 does not see) root RAID device /dev/md0
On Tue, May 12, 2009 at 9:11 AM, martin f krafft <madduck@debian.org> wrote:
> also sprach Tony Godshall <togo@of.net> [2009.05.11.2058 +0200]:
>> They are *not*. That would seem to be the nub of the problem. No
>> base partitions, thus no RAID. Good, thanks, that's progress. Might
>> be good for md to report that that a little better (see screenshot).
>> Oh, duh, I moved /etc/mdadm/mdadm.conf out of the way. So it doesn't
>> even know I have a RAID until it autodetects it, right? Oh, wait, in
>> this initramfs environment there is an /etc/mdadm/mdadm.conf, and it
>> shows UUID and the 4-way RAID1. What, so the /etc/mdadm/mdadm.conf
>> inside the initrd is not from the kernel package but was built
>> locally? Didn't realize that.
>
> It's copied from the main system when the initramfs is created,
> unless it's faulty or doesn't represent the system or hasn't been
> checked since the 2.5.3 upgrade.
>
> In the initramfs, if there is a config file, it's used. If there's
> not a config file, mdadm scans all partitions and assembles them all
> (like /sbin/mdadm-startall).
Yes, I see that it's optional, and actually rather pointless in my
case since I'm booting off the RAID partition, unless grub reads
mdadm.conf . But grub only reads /boot, not /etc, right? /etc would
not be available until /etc/fstab is processed.
> Thus, if you remove it in the initramfs, you basically tell the
> system that you want it to scan, rather than search for the specific
> UUID in the file.
>
>> Perhaps if I could figure out how to grab the dmesg output from
>> initramfs environment, I could then compare the amd64 kernel
>> output to the 686-bigmem kernel output... :-/
>
> Append 'break=bottom debug' to the kernel line and at the shell do
> something like
>
> mount -o remount,rw /root
> cp /dev/.initramfs/initramfs.debug /root/root/initramfs-debug.foo
> mount -o remount,ro /root
>
> and then find the file in /root once the system booted.
Thanks! I'll try this on Thursday.
Now that I have a better idea of what's going on during the boot
process, I googled and found this:
http://wiki.debian.org/InitramfsDebug
Wish I'd found it earlier. I could have submitted a much better
initial report. By the way, Martin, sometimes it's good to give
people a little more "why" with the "do this", "do that". Or point
them to a good wiki or faq. Bug reporters don't necessarily choose to
be ignorant and a word to the wise-guy may save a bit of flame. ;-)
Best Regards.
Tony
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