Re: grub-probe seems to be having problems

On Thu, 22 Mar 2012 02:27:17 +0000 (UTC) jlcenter@comcast.net wrote:

Any takers?  -John

Without the "details in the previous mail", there isn't much to take...

NeilBrown

----- Forwarded Message -----
From: "Vladimir 'φ-coder/phcoder' Serbinenko" <redacted>
To: "Lennart Sorensen" <redacted>
Cc: "The development of GRUB 2" <redacted>, "Marco d'Itri" <redacted>
Sent: Tuesday, March 20, 2012 6:28:18 AM
Subject: Re: grub-probe seems to be having problems

On 19.03.2012 22:28, Lennart Sorensen wrote:

quoted

On Fri, Mar 09, 2012 at 03:37:57PM -0500, Lennart Sorensen wrote:

quoted

Interestingly after poking at reading all the disks and poking mdadm
--examine and --detail, now grub-prob likes md1, but still dislikes md0.

root@rceng03new:/tmp# /usr/sbin/grub-probe --device-map= --target=abstraction --device /dev/md1
diskfilter mdraid1x raid5rec
root@rceng03new:/tmp# /usr/sbin/grub-probe --device-map= --target=abstraction --device /dev/md0
/usr/sbin/grub-probe: error: Couldn't find physical volume `(null)'. Check your device.map.

md1 was failing before with the same grub code.

I don't get it.  I wonder if there is any known issues in 2.6.32 kernel
and/or mdadm - v3.1.4 - 31st August 2010

Any suggestion for how to try and debug this myself, like which
file/function to start debuging at?  I would like to put this machine
in to production use soon, but I would also like to take this chance to
fix the bug in grub first.

There is no need to debug. I know exactly why GRUB is confused: because 
as far as my understanding goes the superblock makes no sense (details 
in previous mail). What we need is that someone familiar with md tells 
me how this sector should be interpreted.