Xen users - Jul 2010 - Error occur when boot domU:mount: mounting none on /dev failed: No such device

Hi,

I installed xen 4.0 on Ubuntu 10.04 (Lucid), and success to boot with
xen-4.0.gz and 2.6.31.13 kernel.
As documents said, the 2.6.31.13 kernel can be used as dom0, as well as
domU, so I tried to use it to crate my first domU.

first I use debootstrap to create my basic file system for the domU, and
then write the configure file as follow
*1 kernel="/boot/vmlinuz-2.6.31.13"*
*  2 ramdisk="/boot/initrd.img-2.6.31.13"*
*  3 name="myvm"*
*  4 memory=256*
*  5 #bootloader="/usr/bin/pygrub"*
*  6 #boot="c"*
*  7 #dhcp="dhcp"*
*  8
disk=[''file:/home/sluo/xen/vm/myvm.img,hda1,w'',''file:/home/sluo/xen/vm/myvm.
swap,hda2,w'']*
*  9 vif=['''']*
* 10 #root="/dev/sda2 ro"*
* 11 root="UUID=37b781b3-0373-4f04-9230-42708e24c9aa ro"*
* 12 rootdelay=120*
* 13 extra="earlyprintk=xen nomodeset initcall_debug debug
loglevel=10"*

After this, i run ''#xm create myvm.cfg'' and succeed to get vm
created, then
run ''xm console myvm''
The domU goes started, but when loading kernel, it stopped the error, and
goes to initramfs prompt:
*Loading, please wait...*
*mount: mounting none on /dev failed: No such device*


*BusyBox v1.13.3 (Ubuntu 1:1.13.3-1ubuntu11) built-in shell (ash)*
*Enter ''help'' for a list of built-in commands.*

*(initramfs) *

Sometimes, it will give another error message saying "Give up waiting for
root device", just as following:*

*
*Gave up waiting for root device.  Common problems:*
*  - Boot args (cat /proc/cmdline)*
*    - Check rootdelay= (did the system wait long enough?)*
*    - Check root= (did the system wait for the right device?)*
*  - Missing modules (cat /proc/modules; ls /dev)*
* ALERT! /dev/sda2 does not exist. Dropping to a shell!*

I search a lot by google, but seems no result to resolve my problem
completely ..........


Anyone have idea about this? Attached is information of my system ... Any
other information needed, please tell me!

Thanks,
Sean



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On Fri, Jul 30, 2010 at 11:17 AM, Sean Shoufu Luo <luoshoufu@gmail.com>
wrote:
> 1 kernel="/boot/vmlinuz-2.6.31.13"
>   2 ramdisk="/boot/initrd.img-2.6.31.13"
>  13 extra="earlyprintk=xen nomodeset initcall_debug debug
loglevel=10"
Short anwer: you haven''t tell the domU kernel where the root
filesystem is. You''d need at least "root" and
"console" pairs on extra
line.
See http://lists.xensource.com/archives/html/xen-users/2010-06/msg01113.html
for similar issue.

-- 
Fajar

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