[virt-tools-list] kvm disk storage error

[Hui Kai Ran]

Hi, all

when I use virt-manager to create VM, it ended in an error.the following
is my step to create VM

[ENV]:
RHEL6.1 x86_64
[root at localhost ~]# uname -a
Linux localhost.localdomain 2.6.32-131.0.15.el6.x86_64 #1 SMP Tue May 10
15:42:40 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux
[root at localhost ~]# rpm -qa libvirt
libvirt-0.8.7-18.el6.x86_64
[root at localhost ~]# rpm -qa qemu-kvm
qemu-kvm-0.12.1.2-2.160.el6.x86_64

I have two disk:
/dev/sda : 8589MB
/dev/sdb : 4294 MB

1. I created one "disk:Physical Disk Device" storage pool on /dev/sdb
with the name "disk2"
2. created 4GB storage volume "sdb1" on "disk2"
3. create a new VM on storage volume "sdb1" and ended in the following
error

Unable to complete install:'Capacity must be a positive number'