[root@ns ~]# xm create -c www                // start guestOS  
we got these errors after executing above command
.........................
Making device-mapper control node
Scanning logical volumes
  Reading all physical volumes.  This may take a while...
  No volume groups found
Activating logical volumes
  Volume group "Xen" not found
Creating root device.
Mounting root filesystem.
mount: could not find filesystem '/dev/root'
Setting up other filesystems.
Setting up new root fs
setuproot: moving /dev failed: No such file or directory
no fstab.sys, mounting internal defaults
setuproot: error mounting /proc: No such file or directory
setuproot: error mounting /sys: No such file or directory
Switching to new root and running init..
unmounting old /dev
unmounting old /proc
unmounting old /sys
switchroot:
 mount failed: No such file or directory
Booting has failed.
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domU's config file:
kernel= "/boot/vmlinuz-2.6.21-2950.fc8xen"
ramdisk= "/boot/initrd-2.6.21-2950.fc8xen.img"
memory= "256"
name= "www"
vcpus= "1"
nicks= "1"
vif= [ 'mac=00:16:3e:00:00:11,bridge=xenbr0' ]
disk= [ 'phy:Xen/www00,hda1,w',
'phy:Xen/www01,hda2,w',
'phy:Xen/www02,hda3,w',
'phy:Xen/www03,hda4,w',
'phy:Xen/www04,hda5,w' ]
root= "/dev/hda1 ro"
extra= "3"
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fstab for domU
/dev/hda1               /                       ext3    defaults        1 1
/dev/hda3               /usr                    ext3    defaults        1 2
/dev/hda5               /tmp                   
 ext3    defaults        1 2
/dev/hda4               /var                    ext3    defaults        1 2
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0
 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
/dev/hda2               swap                    swap    defaults        0 0  
 
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fstab for dom0
/dev/Xen/Host00         /                       ext3    defaults        1 1
/dev/Xen/Host03         /var                    ext3    defaults        1 2
/dev/Xen/Host05         /home                   ext3    defaults        1
 2
/dev/Xen/Host02         /usr                    ext3    defaults        1 2
/dev/Xen/Host04         /tmp                    ext3    defaults        1 2
/dev/sda1               /boot                   ext3    defaults        1 2
tmpfs                  
 /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                  
 proc    defaults        0 0
/dev/Xen/Host01         swap                    swap    defaults        0 0
-------------------------------------------------------------------------------