Xen users - May 2013 - ALERT! /dev/xvda2 does not exist. Dropping to a shell!

Dear All,

Can''t start system because kernel can''t load file systems to
and get the
next error:

modprobe: can''t load module microcode
(kernel/arch/x86/kernel/microcode.ko): No such device
done.
Begin: Running /scripts/init-premount ... Begin: Requesting microcode
update using per-core interface ... done.
done.
Begin: Mounting root file system ... Begin: Running /scripts/local-top ...
[    1.493127] device-mapper: uevent: version 1.0.3
[    1.493908] device-mapper: ioctl: 4.22.0-ioctl (2011-10-19)
initialised: dm-devel@redhat.com
  Volume group "disco-xen-server" not found
  Skipping volume group disco-xen-server
Unable to find LVM volume disco-xen-server/xen-server-swap
done.
Begin: Waiting for root file system ... done.
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/xvda2 does not exist.  Dropping to a shell!
modprobe: module ehci-hcd not found in modules.dep
modprobe: module uhci-hcd not found in modules.dep
modprobe: module ohci-hcd not found in modules.dep
modprobe: module usbhid not found in modules.dep


BusyBox v1.20.2 (Debian 1:1.20.0-7) built-in shell (ash)
Enter ''help'' for a list of built-in commands.

/bin/sh: can''t access tty; job control turned off
(initramfs)

Anyone can helpme because i''m lost with this matter i don''t
know if the
configuration is grong or if the module to create xvda2 is not loaded i
don''t know follow can see some information about my system:

root@xen-servidor:~# uname -r
3.2.0-4-amd64
root@xen-servidor:~#

root@xen-servidor:~# xm info test
host                   : xen-servidor
release                : 3.2.0-4-amd64
version                : #1 SMP Debian 3.2.41-2+deb7u2
machine                : x86_64
nr_cpus                : 2
nr_nodes               : 1
cores_per_socket       : 2
threads_per_core       : 1
cpu_mhz                : 1297
hw_caps                :
178bf3ff:efd3fbff:00000000:00001310:00802001:00000000:0008377f:00000000
virt_caps              : hvm
total_memory           : 895
free_memory            : 0
free_cpus              : 0
xen_major              : 4
xen_minor              : 1
xen_extra              : .4
xen_caps               : xen-3.0-x86_64 xen-3.0-x86_32p hvm-3.0-x86_32
hvm-3.0-x86_32p hvm-3.0-x86_64
xen_scheduler          : credit
xen_pagesize           : 4096
platform_params        : virt_start=0xffff800000000000
xen_changeset          : unavailable
xen_commandline        : placeholder
cc_compiler            : gcc version 4.7.2 (Debian 4.7.2-5)
cc_compile_by          : carnil
cc_compile_domain      : debian.org
cc_compile_date        : Sun May  5 14:44:49 UTC 2013
xend_config_format     : 4
root@xen-servidor:~#

root@xen-servidor:~# df -hT
S.ficheros                                        Tipo     Tamaño Usados 
Disp Uso% Montado en
rootfs                                            rootfs     4,6G   2,4G 
2,3G  52% /
udev                                              devtmpfs    10M      0  
10M   0% /dev
tmpfs                                             tmpfs       74M   280K  
74M   1% /run
/dev/mapper/disco--xen--server-xen--server--root  ext4       4,6G   2,4G 
2,3G  52% /
tmpfs                                             tmpfs      5,0M      0 
5,0M   0% /run/lock
tmpfs                                             tmpfs      148M      0 
148M   0% /run/shm
/dev/mapper/disco--xen--server-xen--server--disco ext4       223G    83G 
141G  38% /disco
root@xen-servidor:~#

test.cfg

#
#  Kernel + memory size
#
kernel      = ''/boot/vmlinuz-3.2.0-4-amd64''
ramdisk     = ''/boot/initrd.img-3.2.0-4-amd64''

vcpus       = ''1''
memory      = ''128''

#
#  Disk device(s).
#
root        = ''/dev/xvda2 ro''
disk        = [
                 
''file:/home/xen/domains/test/disk.img,xvda2,w'',
                 
''file:/home/xen/domains/test/swap.img,xvda1,w'',
              ]


#
#  Physical volumes
#


#
#  Hostname
#
name        = ''test''

#
#  Networking
#
vif         = [ ''ip=192.168.0.254 ,mac=00:16:3E:3A:FD:80'' ]

#
#  Behaviour
#
on_poweroff = ''destroy''
on_reboot   = ''restart''
on_crash    = ''restart''

Best Regards.

Ignacio Alegre