RE: [Xen-users] Problem with xen boot if DOM0 is on the LVM, which is on RAID

["Artur Linhart - Linux communication" <AL.LINUX@xxxxxxxxxxx>]

Hello,

        Thanks for response :-)

I verified the kernel configurations, they are different - sure - but in the
area of the MD/LVM this is very similar (the only difference is, the Xen
kernel has for CONFIG_BLK_DEV_MD the value "y", by the Ubuntu default kernel
it is the value "m"), so it's looks for me like this is rather not the
problem I have... Or what do You think?
In the /dev/mapper directory is only 1 character device with the name
"control"
After the system comes in the state described below,  there is such a "
prompt" 
(initramfs)
And the cursor is blinking there, I can use some shell commands of the xen.
If I start lvm, I can by lvdisplay, vgdisplay, pvdisplay see the given
entities like I have defined it and used in Ubuntu direct, but that is all -
it looks like the device in /dev/mapper just would not be created and I do
not have any Idea why or what should I do...

        With best regards, Archie.

P.S. The section dedicated to RAID/LVM in the kernel configurations:

***** config-2.6.18-xen
#
# Multi-device support (RAID and LVM)
#
CONFIG_MD=y
CONFIG_BLK_DEV_MD=y
CONFIG_MD_LINEAR=m
CONFIG_MD_RAID0=m
CONFIG_MD_RAID1=m
CONFIG_MD_RAID10=m
CONFIG_MD_RAID456=m
CONFIG_MD_RAID5_RESHAPE=y
CONFIG_MD_MULTIPATH=m
CONFIG_MD_FAULTY=m
CONFIG_BLK_DEV_DM=m
CONFIG_DM_CRYPT=m
CONFIG_DM_SNAPSHOT=m
CONFIG_DM_MIRROR=m
CONFIG_DM_ZERO=m
CONFIG_DM_MULTIPATH=m
CONFIG_DM_MULTIPATH_EMC=m

***** CONFIG-2.6.20-15-SERVER
#
# Multi-device support (RAID and LVM)
#
CONFIG_MD=y
CONFIG_BLK_DEV_MD=m
CONFIG_MD_LINEAR=m
CONFIG_MD_RAID0=m
CONFIG_MD_RAID1=m
CONFIG_MD_RAID10=m
CONFIG_MD_RAID456=m
CONFIG_MD_RAID5_RESHAPE=y
CONFIG_MD_MULTIPATH=m
CONFIG_MD_FAULTY=m
CONFIG_BLK_DEV_DM=m
# CONFIG_DM_DEBUG is not set
CONFIG_DM_CRYPT=m
CONFIG_DM_SNAPSHOT=m
CONFIG_DM_MIRROR=m
CONFIG_DM_ZERO=m
CONFIG_DM_MULTIPATH=m
CONFIG_DM_MULTIPATH_EMC=m

-----Original Message-----
From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Vladislav Kurz
Sent: Wednesday, May 30, 2007 10:08 AM
To: xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] Problem with xen boot if DOM0 is on the LVM,which
is on RAID

On Tuesday 29 May 2007 20:45, Artur Linhart - Linux communication wrote:
> Hello,
>
>
>
>             I have problems with booting with the new Xen (used the binary
> tarball) v. 3.1.0.
>
>
>
> I have installed following system:
>
> One small raid partition with Ext3 fs with the boot directorz and grub
> installed
>
> Two large and one small mirrored raid1 partitions managed by mdadm and
used
> as 3 physical volumes for LVM, all 3 joined into one volume group.
>
> Planned dom0 system is installed on the logical volume, which is striped
> over md1 and md3 raid phzsical volumes. It is Ubuntu server 7.04.
>
> The Ubuntu system self boots ad behaves normally.
>

I have similar configuration without any problems:

Debian etch + xen 3.0.3
/boot of dom0 on (hardware) raid1 + ext3
root of dom0 & everything else on raid1 + lvm + ext3
I use xen kernel provided by debian

>
> If booting Xen, the boot process comes to the point where the raid arrays
> are beeing initialized. The RAID arrays itself are initialized and
> activated correctly. After it happens, the system hangs for some minutes
> and then the message comes:
>
>
>
> Check root= bootarg cat /proc/cmdline
>
> or missing modules, devices: cat /proc/modules ls /dev
>
> ALERT! /dev/mapper/VG_HIGHLAND_SYSTEM-LV_DOM0 does not exist. Dropping to
> shell!
>
>
>
>
> ... and the sh is invoked, the tty cannot be accessed, so the job control
> is turned off.
>
> I looked into /devúmapper and really, thre is no VG_HIGHLAND_SYSTEM volume
> group, which appears there if booting the Ubuntu server.
>

Check if there is something else in /dev/mapper

>
>
> I am not very skilled in the work with LVM, so the only thing what came
> into my mind  was - it looks like if the default binary tarball of Xen
> 3.1.0 has not turned on the LVM support in the kernel, but I think this is
> not possible, because LVM is normally used.
>
> Or would it be the solution to configure and compile the kernel from
> source?

before compiling your own, compare the configuration of ubuntu ditstro
kernel, 
and xen kernel, expecially CONFIG_MD_* and CONFIG_DM_* options, to find if 
there is support for LVM.

If the support for LVM is in your xen kernel, then check the contents of 
initrd if there are scripts that activate the logical volume 
i.e. /sbin/vgchange, /scripts/*/lvm

Anyway even if you compile your own kernel you might need initrd to activate

LVM.

> I found the idea this is some error in GRUB script, but I do not know if
it
> is my case - GRUB configuration file "menu.lst" looks like:
>
>
>
> title     Xen 3.1.0, kernel 2.6.18-xen /dev/sda1
> root      (hd0,0)
> kernel    /xen-3.1.0.gz dom0_mem=192M
> module    /vmlinuz-2.6.18-xen root=/dev/mapper/VG_HIGHLAND_SYSTEM-LV_DOM0
> ro max_loop=255 console=tty0
> module    /initrd.img-2.6.18-xen
>

This is OK, I have similar config

-- 
Regards
        Vladislav Kurz


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