lvcreate 创建snapshot 报错，求助

poemshop

使用lvcreate 出错，  device-mapper targets not detected,
请问该如何解决， 谢谢

[root@localhost ~]# lvcreate -L 10M -p r -s -n data2backup /dev/vg0/data2
  snapshot: Required device-mapper target(s) not detected in your kernel

[root@localhost ~]# uname -a
Linux localhost.localdomain 2.6.9-22.EL #1 Mon Sep 19 17:49:49 EDT 2005 x86_64 x86_64 x86_64 GNU/Linux