1.how to reproduce: (1)just use LVM disk,leave libvirt create vg (2)xml: <pool type='logical'> <name>pic_pool2</name> <source> <device path='/dev/sdb1'/> <device path='/dev/sdb2'/> </source> <target> <path>/dev/pic_pool2</path> </target> </pool> (3)steps: a.start libvirtd,copy xml b.virsh pool-define lvm_pool.xml c.virsh pool-list --all lvm_pool exsists c.virsh pool-create lvm_pool.xml lvm_pool disappears 2.analyze: here pool-create fails because of vg has not been built before "vgchange",and pool-create will delete pool-def after failure. pool-create can fail because a lot of reasons, but it doesn't mean previous pool definition should be obselete,previous definition should remain unchanged if following pool management fails. 3.fix: shall we make backend->startPool gurantee pool unchanged in condition of start fails or offer an undo function after failure?