Hi Daniel and other developers, We have programed a HLFS(HDFS based Log-Structured FileSystem) driver for QEMU, which you can see it here. http://cloudxy.googlecode.com/svn/trunk/hlfs/patches/hlfs_driver_for_qemu_1.... And i have tested in QEMU environment, which works well for us. Now, we wanna add a HLFS driver(Volume storage) for Libvirt(The same as Sheepdog) but i am not sure how to test HLFS driver for Libvirt. How could i know if the HLFS driver for Libvirt works well? I guess libvirt uses qemu interfaces(QEMU way) to finish the real jobs like create/delete volumes. I wanna use command 'virsh' to finish them, which the logical procedure like this: virsh --> libvirt client --> libvirt server --> QEMU Therefore, 'virsh' cannot work for me. I do not know how to test it with command 'virsh' solely. Or maybe i must build QEMU environment for this test, right? In brief, i am not clear about the relationships between Libvirt and QEMU. How do they(QEMU and Libvirt) communicate with each other? How could i test create/delete volumes of Sheepdog/HLFS only with Libvirt environment? Could anyone give me some suggestions? Thanks in advance;-) -- Thanks Harry Wei