On 12 Nov 2015 13:27, "Han Han" <hhan@redhat.com> wrote:
>
> It says that  Logical volume centos_hyv2/swap in use. Maybe centos_hyv2/swap is mounted. So I think you should umount or
> swapoff centos_hyv2/swap first, make sure it is not used by other process. Then try pool-destroy.
>

Yes, that's the system swap. That and home and root are all in the storage pool and are, of course, all in use and I can't run the machine without them being in use. Perhaps if I rm'd the storage pool definition file? Do you think that  would work or is it too dangerous?