Your message dated Sun, 6 Jul 2008 16:37:35 +0200
with message-id <[EMAIL PROTECTED]>
and subject line Re: Bug#432154: LVM not working when *any* md array degraded
has caused the Debian Bug report #432154,
regarding LVM not working when *any* md array degraded
to be marked as done.
This means that you claim that the problem has been dealt with.
If this is not the case it is now your responsibility to reopen the
Bug report if necessary, and/or fix the problem forthwith.
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--
432154: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=432154
Debian Bug Tracking System
Contact [EMAIL PROTECTED] with problems
--- Begin Message ---
Package: grub-pc
Version: 1.95+20070626-1
Severity: normal
I have the following disk setup:
ARRAY /dev/md0 level=raid1 num-devices=2
UUID=35350c38:74a95022:4eeb7f3f:b5bc804c devices=/dev/sdc1,/dev/sdd1
ARRAY /dev/md1 level=raid1 num-devices=2
UUID=3c0b822d:7ad0dd9a:997fa798:3fa99da6 devices=/dev/sdc2,/dev/sdd2
ARRAY /dev/md2 level=raid1 num-devices=2
UUID=e70dddb8:ff6cc34d:9cc0d25e:24d7f956 devices=/dev/sda1,/dev/sdb1
ARRAY /dev/md3 level=raid1 num-devices=2
UUID=c3425a67:34302754:8254f148:ae65912a devices=/dev/sda4,/dev/sdb4
The md0 array is a LVM PV used by the "ares" VG:
ares-root /
ares-home /home
ares-srv /srv
ares-swap
All filesystems are ext3, except for md3, which is reiserfs.
Note that / and /boot are on LVM, on RAID1. While grub-probe does not
correctly detect the necessary modules (pc lvm raid ext2), manually
creating core.img and installing it allows grub to boot directly from
(ares-root).
However... I simulated the death of /dev/sdb (or it may have been sda,
I forget). When I booted, instead of the grub terminal I was
presented with
Welcome to GRUB!
Entering into rescue mode...
grub rescue> _
lsmod reported that the raid and lvm modules were definitely loaded.
Attempting to do "insmod normal" resulted in the "error: unknown
device." Running the command "ls" printed a number of (mdX), (hdX)
and (hdX,Y) devices, but no LVM devices -- that is, (ares-X).
I COULD NOT WORK OUT HOW TO GET GRUB PAST THE RESCUE STAGE.
Fortunately, lilo was on another MBR, and it successfully booted from
/dev/mapper/ares-root. After fiddling with all sorts of knobs, I
eventually gave up trying to get grub to work again, and waited for an
hour while /dev/md3 rebuilt. (md2 is quite small and was rebuilt
before I started fiddling.) Once all the raid arrays were all fully
functional, GRUB suddenly started working correctly again.
Since md3 had absolutely nothing to do with md0 and ares-root -- it
wasn't even on the same disks -- my initial suspicion is that grub
cannot currently boot from an LVM-on-RAID1 /boot if there are *any*
degraded arrays on the system. This strikes me as a VERY VERY BAD
thing -- you need an OS to rebuild the array, and you need the array
rebuilt for grub to boot an OS. Without an external unwedge like LILO
or an OS on a non-LVM partition, it seems impossible to get the
machine back up.
Additional notes:
While the array was degraded, "grub-probe /" gave the error "unknown
device" (IIRC), and update-grub terminates unsuccessfully. When all
arrays working, "grub-probe /" gives the error "Unknown partition
map", and update-grub terminates successfully. In both cases
'grub-install (hd0)' terminates unsuccessfully.
Finally, a very big thanks to the maintainer for holding my hand in
#grub on freenode for a couple of hours while I raged at rescue mode,
etc.
-- Package-specific info:
*********************** BEGIN /boot/grub/device.map
(hd0) /dev/sdc
(hd1) /dev/sdd
(hd2) /dev/sda
(hd3) /dev/sdb
*********************** END /boot/grub/device.map
*********************** BEGIN /boot/grub/grub.cfg
set default=0
set timeout=5
set root=(ares-root)
font (ares-root)/usr/share/grub/unifont.pff
set gfxmode=1024x768
insmod gfxterm
insmod vbe
terminal gfxterm
menuentry "Debian GNU/Linux" {
linux (ares-root)/vmlinuz root=/dev/mapper/ares-root ro vga=790
initrd (ares-root)/initrd.img
}
menuentry "Debian GNU/Linux (single-user mode)" {
linux (ares-root)/vmlinuz root=/dev/mapper/ares-root ro vga=790 singl
e
initrd (ares-root)/initrd.img
}
menuentry "Debian GNU/Linux (rescue partition)" {
linux (md1)/vmlinuz root=/dev/md1 ro vga=790
initrd (md1)/initrd.img
}
menuentry "Debian GNU/Linux (old partition)" {
linux (md2)/vmlinuz root=/dev/md2 ro vga=790
initrd (md2)/initrd.img
}
*********************** END /boot/grub/grub.cfg
-- System Information:
Debian Release: 4.0
APT prefers stable
APT policy: (500, 'stable')
Architecture: i386 (i686)
Shell: /bin/sh linked to /bin/bash
Kernel: Linux 2.6.18-4-686
Locale: LANG=en_AU.UTF-8, LC_CTYPE=en_AU.UTF-8 (charmap=UTF-8)
Versions of packages grub-pc depends on:
ii libc6 2.3.6.ds1-13 GNU C Library: Shared libraries
ii liblzo2-2 2.02-2 data compression library
grub-pc recommends no packages.
-- no debconf information
--- End Message ---
--- Begin Message ---
On Sun, Jul 06, 2008 at 05:10:57PM +1000, Trent W. Buck wrote:
> On Sun, Feb 03, 2008 at 08:44:38PM +0100, Robert Millan wrote:
> > On Sun, Jul 08, 2007 at 11:07:41AM +1000, Trent Buck wrote:
> >> Note that / and /boot are on LVM, on RAID1. While grub-probe does
> >> not correctly detect the necessary modules (pc lvm raid ext2),
> >> manually creating core.img and installing it allows grub to boot
> >> directly from (ares-root).
> >
> > Please try the latest version. Does grub-probe detect the correct
> > modules now?
>
> Sorry I didn't reply earlier. I can only presume that I *meant* to
> test this, but didn't get around to it. Nowadays I only run grub2 on
> one box, which is my Etch file server. I'm rather too nervous to play
> with grub on it.
>
> If I remember, I'll set up a virtual machine at work running sid with
> the same disk configuration, and see if current grub-probe works, but
> realistically I'll probably forget about it.
There has been many improvements on the LVM-on-RAID front, so I can only
assume the problem's been fixed.
If you get around to test it again, and turns out not to be, please reopen
or file a new bug.
Thanks
--
Robert Millan
<GPLv2> I know my rights; I want my phone call!
<DRM> What good is a phone call… if you are unable to speak?
(as seen on /.)
--- End Message ---
