Bug#637254: grub-pc: "unknown LVM metadata header" on mdadm raid1 + lvm

[Yaroslav Leonov]

I didn't get you about missing "-d"
mirror0-lvroot is a correct symlink to block device.

alzgrinew:~# ls -l /dev/mapper/mirror0-lvroot /dev/dm-0
brw-rw---- 1 root disk 253, 0 Sep  9 23:20 /dev/dm-0
lrwxrwxrwx 1 root root      7 Sep  9 23:20 /dev/mapper/mirror0-lvroot -> ../dm-0
alzgrinew:~#

The real problem i created this bugreport is that i end up with unbootable
system after upgrading grub (1.98* ---> 1.99*). Sure, all output in my letters
was done with fresh 1.99* installed.

I've traced grub-pc postinst script (set -x) and found exact problem:

===8<===
alzgrinew:~# grub-install --force --no-floppy /dev/sda
error: unknown LVM metadata header.
error: unknown LVM metadata header.
error: unknown LVM metadata header.
error: unknown LVM metadata header.
error: unknown LVM metadata header.
/usr/sbin/grub-setup: warn: Your embedding area is unusually small.
core.img won't fit in it..
/usr/sbin/grub-setup: error: embedding is not possible, but this is
required when the root device is on a RAID array or LVM volume.
alzgrinew:~#

alzgrinew:~# grub-setup /dev/sda
error: unknown LVM metadata header.
grub-setup: warn: Your embedding area is unusually small.  core.img
won't fit in it..
grub-setup: error: embedding is not possible, but this is required
when the root device is on a RAID array or LVM volume.
alzgrinew:~#
===>8===


here is output you've requested:

alzgrinew:~# grub-probe -t fs -d /dev/mapper/mirror0-lvroot -v
grub-probe: info: Scanning for dmraid_nv RAID devices on disk hd0.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Scanning for dmraid_nv RAID devices on disk hd1.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: scanning hd0 for LVM.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: no LVM signature found.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: scanning hd1 for LVM.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: no LVM signature found.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: Scanning for mdraid09 RAID devices on disk hd0.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Scanning for mdraid09 RAID devices on disk hd1.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: Scanning for mdraid1x RAID devices on disk hd0.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Scanning for mdraid1x RAID devices on disk hd1.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: Scanning for mdraid09 RAID devices on disk hd0.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Scanning for mdraid09 RAID devices on disk hd0,msdos2.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Scanning for mdraid09 RAID devices on disk hd0,msdos1.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Found array md127 (mdraid09).
grub-probe: info: Scanning for mdraid09 RAID devices on disk hd1.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: Scanning for mdraid09 RAID devices on disk hd1,msdos2.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: Scanning for mdraid09 RAID devices on disk hd1,msdos1.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: Scanning for mdraid1x RAID devices on disk md127.
grub-probe: info: Scanning for mdraid1x RAID devices on disk hd0.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Scanning for mdraid1x RAID devices on disk hd0,msdos2.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Found array md/2 (mdraid1x).
grub-probe: info: Scanning for mdraid1x RAID devices on disk hd0,msdos1.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: Scanning for mdraid1x RAID devices on disk hd1.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: Scanning for mdraid1x RAID devices on disk hd1,msdos2.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: Scanning for mdraid1x RAID devices on disk hd1,msdos1.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: scanning md/2 for LVM.
grub-probe: info: no LVM signature found.
grub-probe: info: scanning md127 for LVM.
grub-probe: info: scanning hd0 for LVM.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: no LVM signature found.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: scanning hd0,msdos2 for LVM.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: unknown LVM metadata header
.
error: unknown LVM metadata header.
grub-probe: info: scanning hd0,msdos1 for LVM.
grub-probe: info: the size of hd0 is 976773168.
grub-probe: info: scanning hd1 for LVM.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: no LVM signature found.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: scanning hd1,msdos2 for LVM.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: no LVM signature found.
grub-probe: info: scanning hd1,msdos1 for LVM.
grub-probe: info: the size of hd1 is 976773168.
grub-probe: info: opening mirror0-lvroot.
ext2
alzgrinew:~#

2011/9/28 Vladimir 'φ-coder/phcoder' Serbinenko <phcoder at gmail.com>:
> On 28.09.2011 16:50, Yaroslav Leonov wrote:
>> raid mdraid09 lvm
>> alzgrinew:~#
> that worked perfectly. Actually in your command -d was missing. Could
> you try replacing -t abstraction with -t fs?
> Reading your report I see no bug whatsoever other than a non-blocking
> warning (which is legitimate although may be confusing)
>
> --
> Regards
> Vladimir 'φ-coder/phcoder' Serbinenko
>
>
>



-- 


C уважением, Ярослав Леонов.