On 07/15/2014 08:28 AM, Ravi Samji wrote:

Hi All,

I'm having issue with creating LVM Volume via libvirt.

We are running libvirtd 1.2 with KVM.

We are creating Volume Group (VG01) outside of libvirt and defining a storage pool for it. Here is the StoragePool XML for the Volume Group created outside libvirt. <pool type="logical"> <name>VG01</name> <target> <path>/dev/VG01</path> </target> </pool>

We are creating Logical Volume (ub_test01.img) through libvirt in the Volume Group (VG01) Here is the XML to create Storage Volume in LVM Storage Pool VG01. <volume type="block"> <name>ub_test01.img</name> <allocation>0</allocation> <capacity unit="M">1</capacity>

If the allocation is not equal to the capacity, libvirt calls lvcreate with the --virtualsize option, which creates this snapshot that should take up less space. For a regular volume, just omit the allocation element, or use the same values for both.

<target> <format type="lvm2" /> </target> </volume>

When I create the Logical Volume from libvirt using above XML and run lvs command to list logical volumes, this is what I see.

LV VG Attr LSize Origin Snap% Move Log Copy% Convert --------------- ------- ------- ------- ----------------------- ------- ------- ------- ------- ------- foo VG01 -wi-a- 1.00g ub_test01.img VG01 swi-a- 4.00m [ub_test01.img_vorigin] 0.20 root ops-02 -wi-ao 227.08g swap_1 ops-02 -wi-ao 5.75g

As you see, ub_test01.img shows that it has an Origin indicating that it was created as a snapshot, but, that Origin doesn't exist and wasn't specified.

I'd appreciate if you anyone can help me understand what is going on and/or describe how to make libvirt create logical volumes not as a snapshot.

I'm happy to enable debugging to see what command libvirt is running to create the volume if someone case describe how to enable debugging.

See http://libvirt.org/logging.html Jan