Xen users - Jun 2005 - RE: Suse 9.3 "kernel panic - not syncing: VFS: Unable tomount root fs on unknown-block (8, 1)"

It''s possible that the fstab is incorrect inside your image.  Make sure
it is mounting / as /dev/sda1.

David 

-----Original Message-----
From: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of e&v
Sent: Tuesday, June 14, 2005 3:12 PM
To: xen-users@lists.xensource.com
Subject: [Xen-users] Suse 9.3 "kernel panic - not syncing: VFS: Unable
tomount root fs on unknown-block (8, 1)"

hi, hope you can help or at least give me a hint how to proceed.... I
have Xen up and running with a domain0 but having huge problems in
getting additional domains created.

 I followed the instructions in the Suse "readme for xen packages "
->
http://www.suse.de/~garloff/linux/xen/README.SuSE and I get to e)

These are the steps I followed:  
Ad 3) YaST dirinstall
a) Create a root FS image
    - create disc image file (dd if=/dev/zero of=img ...)
    - create file system (mkXYZfs img)
    - mount image (mount -o loop img ...)
 b) start yast2 dirinstall module, select mounted directory as a target,
    select required packages (don''t forget to select XEN kernel, you
need
    some of the kernel modules in the root FS)
 c) create /etc/fstab in the root FS
 d) umount image/FS
 e) configure and start XEN (use the image/FS as storage)

When I use the config below, when starting a new domain with 

xm create configfile vmid=1 -c .... I get the following error in the
start up sequence:

"kernel panic - not syncing: VFS: Unable to mount root fs on
unknown-block (8,1)"

Config.file: 
kernel = "/boot/vmlinuz-2.6.11.4-21.7-xen"
memory = 100
name = "suse931"
nics = 1
ip = "1.2.3.4"
disk = [''file:/home/name/vm1disk,sda1,w'']
root = "/dev/sda1"

By the way I get the same error when trying to start TTYLINUX ... and I
followed the instructions in the Xen Manual
(http://www.cl.cam.ac.uk/Research/SRG/netos/xen/readmes/user/user.html#S
ECTION02330000000000000000

-- 

ciao ev

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hi david & thanks,

the fstab is changed within the image to root / as /dev/sda1 :-)  and
I assume that the ttylinux file rootfs.gz has the same root device
"/dev/sda1" (... you can''t change it anyway)

ciao

On 6/14/05, David_Schmidt@dell.com <David_Schmidt@dell.com>
wrote:
> It''s possible that the fstab is incorrect inside your image.  Make
sure
> it is mounting / as /dev/sda1.
> 
> David
> 
> -----Original Message-----
> From: xen-users-bounces@lists.xensource.com
> [mailto:xen-users-bounces@lists.xensource.com] On Behalf Of e&v
> Sent: Tuesday, June 14, 2005 3:12 PM
> To: xen-users@lists.xensource.com
> Subject: [Xen-users] Suse 9.3 "kernel panic - not syncing: VFS: Unable
> tomount root fs on unknown-block (8, 1)"
> 
> hi, hope you can help or at least give me a hint how to proceed.... I
> have Xen up and running with a domain0 but having huge problems in
> getting additional domains created.
> 
>  I followed the instructions in the Suse "readme for xen packages
" ->
> http://www.suse.de/~garloff/linux/xen/README.SuSE and I get to e)
> 
> These are the steps I followed:
> Ad 3) YaST dirinstall
> a) Create a root FS image
>     - create disc image file (dd if=/dev/zero of=img ...)
>     - create file system (mkXYZfs img)
>     - mount image (mount -o loop img ...)
>  b) start yast2 dirinstall module, select mounted directory as a target,
>     select required packages (don''t forget to select XEN kernel,
you
> need
>     some of the kernel modules in the root FS)
>  c) create /etc/fstab in the root FS
>  d) umount image/FS
>  e) configure and start XEN (use the image/FS as storage)
> 
> When I use the config below, when starting a new domain with
> 
> xm create configfile vmid=1 -c .... I get the following error in the
> start up sequence:
> 
> "kernel panic - not syncing: VFS: Unable to mount root fs on
> unknown-block (8,1)"
> 
> Config.file:
> kernel = "/boot/vmlinuz-2.6.11.4-21.7-xen"
> memory = 100
> name = "suse931"
> nics = 1
> ip = "1.2.3.4"
> disk = [''file:/home/name/vm1disk,sda1,w'']
> root = "/dev/sda1"
> 
> By the way I get the same error when trying to start TTYLINUX ... and I
> followed the instructions in the Xen Manual
> (http://www.cl.cam.ac.uk/Research/SRG/netos/xen/readmes/user/user.html#S
> ECTION02330000000000000000
> 
> --
> 
> ciao ev
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 

-- 


mvh/best regards  ervin

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On Tue, 14 Jun 2005, e&v wrote:
>  hi david & thanks,
>
> the fstab is changed within the image to root / as /dev/sda1 :-)  and
> I assume that the ttylinux file rootfs.gz has the same root device
> "/dev/sda1" (... you can''t change it anyway)
>
> ciao
>
> On 6/14/05, David_Schmidt@dell.com <David_Schmidt@dell.com> wrote:
> > It''s possible that the fstab is incorrect inside your image. 
Make sure
> > it is mounting / as /dev/sda1.
No, this:
> > "kernel panic - not syncing: VFS: Unable to mount root fs on
> > unknown-block (8,1)"
means that the kernel could not recognize /dev/sda1

(8,1) comes from the major and minor numbers, e.g. :

   [root@am3 ~]# ls -ld /dev/sda1
   brw-rw----    1 root     disk       8,   1 Mar 23  2001 /dev/sda1

this would _not_ be an fstab issue, as the boot process has not
gotten that far yet.

> > disk = [''file:/home/name/vm1disk,sda1,w'']
> > root = "/dev/sda1"
are you _sure_ that "/home/name/vm1disk" is correct? and can you
mount it via loopback (my apologies if this has been covered).

"name" seems pretty generic, I suspect you haven''t changed it
to
your userid, or updated it for the path on your system?

"unknown-block" sounds bad... like it isn''t there, as
compared to
being misformatted or the like.

-Tom



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> > disk = [''file:/home/name/vm1disk,sda1,w'']
Try using ''0801'' instead of sda1

On Tue, 2005-06-14 at 13:37 -0700, Tom Brown wrote:
> On Tue, 14 Jun 2005, e&v wrote:
> 
> >  hi david & thanks,
> >
> > the fstab is changed within the image to root / as /dev/sda1 :-)  and
> > I assume that the ttylinux file rootfs.gz has the same root device
> > "/dev/sda1" (... you can''t change it anyway)
> >
> > ciao
> >
> > On 6/14/05, David_Schmidt@dell.com <David_Schmidt@dell.com>
wrote:
> > > It''s possible that the fstab is incorrect inside your
image.  Make sure
> > > it is mounting / as /dev/sda1.
> 
> No, this:
> 
> > > "kernel panic - not syncing: VFS: Unable to mount root fs on
> > > unknown-block (8,1)"
> 
> means that the kernel could not recognize /dev/sda1
> 
> (8,1) comes from the major and minor numbers, e.g. :
> 
>    [root@am3 ~]# ls -ld /dev/sda1
>    brw-rw----    1 root     disk       8,   1 Mar 23  2001 /dev/sda1
> 
> this would _not_ be an fstab issue, as the boot process has not
> gotten that far yet.
> 
> 
> > > disk = [''file:/home/name/vm1disk,sda1,w'']
> > > root = "/dev/sda1"
> 
> are you _sure_ that "/home/name/vm1disk" is correct? and can you
> mount it via loopback (my apologies if this has been covered).
> 
> "name" seems pretty generic, I suspect you haven''t
changed it to
> your userid, or updated it for the path on your system?
> 
> "unknown-block" sounds bad... like it isn''t there, as
compared to
> being misformatted or the like.
> 
> -Tom
> 
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 
-- 
Regards,

David F Barrera
Linux Technology Center
Systems and Technology Group, IBM

"The wisest men follow their own direction. "
                                                        Euripides


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On Tue, 14 Jun 2005, David F Barrera wrote:
> > > disk = [''file:/home/name/vm1disk,sda1,w'']
> Try using ''0801'' instead of sda1
why? The kernel went to the right spot (8,1)...
> > > > "kernel panic - not syncing: VFS: Unable to mount root
fs on
> > > > unknown-block (8,1)"
there just wasn''t anything there... which suggests /home/name/vm1disk
is
somehow not correct.

hhmm, I must be wrong. 2.0.5 won''t let you specify an non existant
file.

   [root@xen1 /etc/xen]# xm create bogus -c
   Using config file "bogus".
   Error: Error creating domain: vbd: Segment not found:  \
     uname=file:/home/name/vm1disk

ok, if I create a bogus file, e.g. not a legit filesystem, I get

   Kernel panic - not syncing: VFS: Unable to mount root fs on
   unknown-block(8,1)

if I now turn around and format that bogus file as a filesystem,
e.g. mke2fs /tmp/delete.me and boot with

   disk = [ ''file:/tmp/delete.me,sda1,w'']

I get past that stage, and instead run into the more normal:

   Warning: unable to open an initial console.
   Kernel panic - not syncing: No init found.  Try passing init      option to
kernel.

The warning indicates there was no /dev/console, and the "no
init" means that there was no /sbin/init program on the
filesystem (no suprise, it was just built for testing, so it was empty).

Anyhow, to cut a long story short...
/home/name/vm1disk file does exist, but apparently is not a valid
filesystem. And that is likely to take more than a few sentences to
explain away :-(

-Tom










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Tom Brown wrote:
> Anyhow, to cut a long story short...
> /home/name/vm1disk file does exist, but apparently is not a valid
> filesystem. And that is likely to take more than a few sentences to
> explain away :-(
It looks like the loopback mounting of this file may be failing, have a 
look in xend-debug.log.

Is /home/name NFS mounted? If so, it might be exported with root squash 
which will cause problems. See if you can loopback mount vm1disk. Try 
copying vm1disk to /tmp and see if you can get the VM to start with 
file:/tmp/vm1disk.

James

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thanks to all of you / the combined ideas you gave me did the trick 
... I have several domins running now!

Next step is to get the network up to speed and the graphical
interface in place  /

Have fun / 

On 6/14/05, Tom Brown <tbrown@baremetal.com>
wrote:
> On Tue, 14 Jun 2005, David F Barrera wrote:
> 
> > > > disk = [''file:/home/name/vm1disk,sda1,w'']
> > Try using ''0801'' instead of sda1
> 
> why? The kernel went to the right spot (8,1)...
> 
> > > > > "kernel panic - not syncing: VFS: Unable to mount
root fs on
> > > > > unknown-block (8,1)"
> 
> there just wasn''t anything there... which suggests
/home/name/vm1disk is
> somehow not correct.
> 
> hhmm, I must be wrong. 2.0.5 won''t let you specify an non existant
file.
> 
>    [root@xen1 /etc/xen]# xm create bogus -c
>    Using config file "bogus".
>    Error: Error creating domain: vbd: Segment not found:  \
>      uname=file:/home/name/vm1disk
> 
> ok, if I create a bogus file, e.g. not a legit filesystem, I get
> 
>    Kernel panic - not syncing: VFS: Unable to mount root fs on
>    unknown-block(8,1)
> 
> if I now turn around and format that bogus file as a filesystem,
> e.g. mke2fs /tmp/delete.me and boot with
> 
>    disk = [ ''file:/tmp/delete.me,sda1,w'']
> 
> I get past that stage, and instead run into the more normal:
> 
>    Warning: unable to open an initial console.
>    Kernel panic - not syncing: No init found.  Try passing init>      
option to kernel.
> 
> The warning indicates there was no /dev/console, and the "no
> init" means that there was no /sbin/init program on the
> filesystem (no suprise, it was just built for testing, so it was empty).
> 
> Anyhow, to cut a long story short...
> /home/name/vm1disk file does exist, but apparently is not a valid
> filesystem. And that is likely to take more than a few sentences to
> explain away :-(
> 
> -Tom
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> _______________________________________________
> Xen-users mailing list
> Xen-users@lists.xensource.com
> http://lists.xensource.com/xen-users
> 

-- 


mvh/best regards  ervin

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