Xen, booting up issue

[Felipe Alfaro Solana]

On 7 Apr 2005, at 13:29, Shahzad Chohan wrote:

> Hi
>
> I've got the following problem when running xen on fedora core 4 Test 
> 1 using, xm create -c rawhide:
>
> VFS: Cannot open root device "mapper/VolGroup00-LogVol00" or 
> unknown-block(0,0)
> Please append a correct "root=" boot option
> Kernel panic - not syncing: VFS: Unable to mount root fs on 
> unknown-block(0,0)
>
> Can anyone please help with this? I've tried mapping different device 
> nodes, but I can't narrow down the problem, my mount looks like this:
>
> /dev/mapper/VolGroup00-LogVol00 on / type ext3 (rw)
> /dev/proc on /proc type proc (rw)
> /dev/sys on /sys type sysfs (rw)
> /dev/devpts on /dev/pts type devpts (rw,gid=5,mode=620)
> /dev/hda1 on /boot type ext3 (rw)
> /dev/shm on /dev/shm type tmpfs (rw)
> none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
> sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
>
> My xen domain file (/etc/xen/rawhide) looks like this
>
> kernel ="/boot/vmlinuz-2.6.11-1.1225_FC4xenU"
> memory = 100
> name = "rawhide"
> nics = 1
> disk = ['file:/root/fedora.img,mapper,w']
> root = "/dev/mapper/VolGroup00-LogVol00 ro"

AFAIK, devmapper isn't supported in domainU. You should instead 
configure your domainU as:

disk = [ 'file:/root/fedora.img,sda1,w']
root = '/dev/sda1 ro'

This will map your loop-based filesystem as /dev/sda1 inside domainU.