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Yasir Assam

2006-Jul-09 01:18 UTC

[Xen-users] Newbie question: Why does Xen boot fail with initrd but succeed with initramfs?

I''m new to Xen. It''s taken me a few days (!) just to get xen
to boot. I
kept getting the following error:

Kernel panic - not syncing: VFS: Unable to mount root fs on 
unknown-block(0,0)

even when I used an initrd image. In the end I tried using mkinitramfs, 
and the resulting image worked.

Why should this be? Nearly every howto I read suggests mkinitrd, yet 
only mkinitramfs works on my system.

The following are the details of what I did:

-------------------------------------------------------------------------------------
I downloaded the xen-unstable source and built it using:

# make world
# make install

and I added the following to the grub menu:

title           Xen 3.0 / XenLinux 2.6
root            (hd0,1)
kernel         /boot/xen-3.0-unstable.gz dom0_mem=262144 noreboot
module         /boot/vmlinuz-2.6.16-3-xen root=/dev/sda2 ro console=tty0

For reference, this is the grub entry for my default kernel (not Xen) - 
I use Debian etch with a custom-built kernel:

title           Debian GNU/Linux, kernel 2.6.17.4-eir
root            (hd0,1)
kernel          /boot/vmlinuz-2.6.17.4-eir root=/dev/sda2 ro
initrd          /boot/initrd.img-2.6.17.4-eir
savedefault
boot

When I reboot and choose Xen from the grub menu, it crashes. The 
following are the last few lines in the log (I had to type these by hand 
- I don''t konw how else to get the log - I don''t think I have
the
hardware needed to set up a terminal via serial link):

md: Autodetecting RAID arrays
md: autorun ...
md: ... autorun DONE.
VFS: Cannot open root device "sda2" or unknown-block(0,0)
Please append correct "root=" boot option
Kernel panic - not syncing: VFS: Unable to mount root fs on 
unknown-block(0,0)

I read this list and thought that maybe it''s because the kernel
doesn''t
have the correct SATA driver. I think I need module sata_nv, and this is 
listed as a module in the config file /boot/config-2.6.16.13-xen.

I also read somewhere that I have to use mkinitrd to create an initrd 
file otherwise modules won''t be loaded, so I exectued the following 
commands:

# depmod 2.6.16.13-xen
# mkinitrd -o /boot/initrd.img-2.6.16.13.xen 2.6.16.13-xen

and I also added the following line to the Xen grub entry:

module          /boot/initrd.img-2.6.16.13.xen

but still I got a crash with the following lines:

md: Autodetecting RAID arrays
md: autorun ...
md: ... autorun DONE.
RAMDISK: cramfs filesystem found at block 0
RAMDISK: Loading 5184KiB [1 disk] into ram disk... done.
Kernel panic - not syncing: VFS: Unable to mount root fs on 
unknown-block(0,0)

Finally, I ran the following:

# depmod 2.6.16.13-xen
# mkinitramfs -k -o /boot/initramfs.img-2.6.16.13.xen 2.6.16.13-xen

and then added the follwing to grub:

module          /boot/initramfs.img-2.6.16.13.xen

and Xen successfully booted on restart.
------------------------------------------------------------------------------

Thanks,
Yasir

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Efraim

2006-Jul-09 01:46 UTC

head link

Re: [Xen-users] Newbie question: Why does Xen boot fail with initrd but succeed with initramfs?

Hi,
Try to compile your kernel with sata or scsi support but no as a module.
Then try:
# depmod 2.6.16.13-xen
# mkinitrd -v --omit-scsi-modules /boot/initrd.img-2.6.16.13.xen
2.6.16.13-xen
and add to grub: "module          /boot/initrd.img-2.6.16.13.xen"
It worked for me.

On 7/9/06, Yasir Assam <list1@endlessvoid.com>
wrote:>
> I''m new to Xen. It''s taken me a few days (!) just to get
xen to boot. I
> kept getting the following error:
>
> Kernel panic - not syncing: VFS: Unable to mount root fs on
> unknown-block(0,0)
>
> even when I used an initrd image. In the end I tried using mkinitramfs,
> and the resulting image worked.
>
> Why should this be? Nearly every howto I read suggests mkinitrd, yet
> only mkinitramfs works on my system.
>
> The following are the details of what I did:
>
>
>
-------------------------------------------------------------------------------------
> I downloaded the xen-unstable source and built it using:
>
> # make world
> # make install
>
> and I added the following to the grub menu:
>
> title           Xen 3.0 / XenLinux 2.6
> root            (hd0,1)
> kernel         /boot/xen-3.0-unstable.gz dom0_mem=262144 noreboot
> module         /boot/vmlinuz-2.6.16-3-xen root=/dev/sda2 ro console=tty0
>
> For reference, this is the grub entry for my default kernel (not Xen) -
> I use Debian etch with a custom-built kernel:
>
> title           Debian GNU/Linux, kernel 2.6.17.4-eir
> root            (hd0,1)
> kernel          /boot/vmlinuz-2.6.17.4-eir root=/dev/sda2 ro
> initrd          /boot/initrd.img-2.6.17.4-eir
> savedefault
> boot
>
> When I reboot and choose Xen from the grub menu, it crashes. The
> following are the last few lines in the log (I had to type these by hand
> - I don''t konw how else to get the log - I don''t think I
have the
> hardware needed to set up a terminal via serial link):
>
> md: Autodetecting RAID arrays
> md: autorun ...
> md: ... autorun DONE.
> VFS: Cannot open root device "sda2" or unknown-block(0,0)
> Please append correct "root=" boot option
> Kernel panic - not syncing: VFS: Unable to mount root fs on
> unknown-block(0,0)
>
> I read this list and thought that maybe it''s because the kernel
doesn''t
> have the correct SATA driver. I think I need module sata_nv, and this is
> listed as a module in the config file /boot/config-2.6.16.13-xen.
>
> I also read somewhere that I have to use mkinitrd to create an initrd
> file otherwise modules won''t be loaded, so I exectued the
following
> commands:
>
> # depmod 2.6.16.13-xen
> # mkinitrd -o /boot/initrd.img-2.6.16.13.xen 2.6.16.13-xen
>
> and I also added the following line to the Xen grub entry:
>
> module          /boot/initrd.img-2.6.16.13.xen
>
> but still I got a crash with the following lines:
>
> md: Autodetecting RAID arrays
> md: autorun ...
> md: ... autorun DONE.
> RAMDISK: cramfs filesystem found at block 0
> RAMDISK: Loading 5184KiB [1 disk] into ram disk... done.
> Kernel panic - not syncing: VFS: Unable to mount root fs on
> unknown-block(0,0)
>
> Finally, I ran the following:
>
> # depmod 2.6.16.13-xen
> # mkinitramfs -k -o /boot/initramfs.img-2.6.16.13.xen 2.6.16.13-xen
>
> and then added the follwing to grub:
>
> module          /boot/initramfs.img-2.6.16.13.xen
>
> and Xen successfully booted on restart.
>
>
------------------------------------------------------------------------------
>
> Thanks,
> Yasir
>
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
>

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Yasir Assam

2006-Jul-09 09:59 UTC

head link

Re: [Xen-users] Newbie question: Why does Xen boot fail with initrd but succeed with initramfs?

Hi Efraim,

I''ll have to try this, but my inderstanding is that I can compile these
as modules providing I use a ramdisk to load them at boot time (my
understaning of all this stuff is shaky though!). 

As I said, I tried mkinitrd and it didn''t work, but mkinitcramfs did.
Why should the latter work but not the former?

Also, on my system the option --omit-scsi-modules doesn''t exist for
mkinitrd (I''m using Debian Etch).

Thanks,

Yasir

  Hi,

  Try to compile your kernel with sata or scsi support but no as
a module.

  Then try:

  # depmod 2.6.16.13-xen

# mkinitrd -v --omit-scsi-modules /boot/initrd.img-2.6.16.13.xen
2.6.16.13-xen

  and add to grub: "module          /boot/initrd.img-2.6.16.13.xen"

It worked for me.

  On 7/9/06, Yasir
Assam &lt;list1@endlessvoid.com&gt;
wrote:
  I''m
new to Xen. It''s taken me a few days (!) just to get xen to boot. I

kept getting the following error:

Kernel panic - not syncing: VFS: Unable to mount root fs on

unknown-block(0,0)

even when I used an initrd image. In the end I tried using mkinitramfs,

and the resulting image worked.

Why should this be? Nearly every howto I read suggests mkinitrd, yet

only mkinitramfs works on my system.

The following are the details of what I did:

-------------------------------------------------------------------------------------

I downloaded the xen-unstable source and built it using:

# make world

# make install

and I added the following to the grub menu:

title           Xen 3.0 / XenLinux 2.6

root            (hd0,1)

kernel         /boot/xen-3.0-unstable.gz dom0_mem=262144 noreboot

module         /boot/vmlinuz-2.6.16-3-xen root=/dev/sda2 ro console=tty0

For reference, this is the grub entry for my default kernel (not Xen) -

I use Debian etch with a custom-built kernel:

title           Debian GNU/Linux, kernel 2.6.17.4-eir

root            (hd0,1)

kernel          /boot/vmlinuz-2.6.17.4-eir root=/dev/sda2 ro

initrd          /boot/initrd.img-2.6.17.4-eir

savedefault

boot

When I reboot and choose Xen from the grub menu, it crashes. The

following are the last few lines in the log (I had to type these by hand

- I don''t konw how else to get the log - I don''t think I have
the

hardware needed to set up a terminal via serial link):

md: Autodetecting RAID arrays

md: autorun ...

md: ... autorun DONE.

VFS: Cannot open root device "sda2" or unknown-block(0,0)

Please append correct "root=" boot option

Kernel panic - not syncing: VFS: Unable to mount root fs on

unknown-block(0,0)

I read this list and thought that maybe it''s because the kernel
doesn''t

have the correct SATA driver. I think I need module sata_nv, and this is

listed as a module in the config file /boot/config-
2.6.16.13-xen.

I also read somewhere that I have to use mkinitrd to create an initrd

file otherwise modules won''t be loaded, so I exectued the following

commands:

# depmod 2.6.16.13-xen

# mkinitrd -o /boot/initrd.img-
2.6.16.13.xen 2.6.16.13-xen

and I also added the following line to the Xen grub entry:

module          /boot/initrd.img-2.6.16.13.xen

but still I got a crash with the following lines:

md: Autodetecting RAID arrays

md: autorun ...

md: ... autorun DONE.

RAMDISK: cramfs filesystem found at block 0

RAMDISK: Loading 5184KiB [1 disk] into ram disk... done.

Kernel panic - not syncing: VFS: Unable to mount root fs on

unknown-block(0,0)

Finally, I ran the following:

# depmod 2.6.16.13-xen

# mkinitramfs -k -o /boot/initramfs.img-2.6.16.13.xen 2.6.16.13-xen

and then added the follwing to grub:

module          /boot/initramfs.img-
2.6.16.13.xen

and Xen successfully booted on restart.

------------------------------------------------------------------------------

Thanks,

Yasir

_______________________________________________

Xen-users mailing list

    Xen-users@lists.xensource.com

    http://lists.xensource.com/xen-users

_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users


_______________________________________________
Xen-users mailing list
Xen-users@lists.xensource.com
http://lists.xensource.com/xen-users

Xen users - Jul 2006 - Newbie question: Why does Xen boot fail with initrd but succeed with initramfs?

[Xen-users] Newbie question: Why does Xen boot fail with initrd but succeed with initramfs?

Re: [Xen-users] Newbie question: Why does Xen boot fail with initrd but succeed with initramfs?

Re: [Xen-users] Newbie question: Why does Xen boot fail with initrd but succeed with initramfs?