On Tue, Jan 30, 2018 at 01:17:21PM +0100, Gionatan Danti wrote: > Hi all, > on a fully patched CentOS 7.4 x86-64, I see the following behavior: > > - when creating a new volumes using vol-create-as, the resulting file is a > qcow2 version 2 (compat=0.10) file. Example: > > [root@gdanti-lenovo vmimages]# virsh vol-create-as default zzz.qcow2 > 8589934592 --format=qcow2 --backing-vol /mnt/vmimages/centos6.img > Vol zzz.qcow2 created
Yes, for sake of backcompat we default to v2 unless something requires v3. You can't use vol-create-as to create a v3 image, you need to use the XML input. Either force the use of v3: <volume> <name>demo.qcow2</name> <capacity>1073741824</capacity> <target> <format type='qcow2'/> <compat>1.1</compat> </target> </volume> Or request some feature that implies v3: <volume> <name>demo.qcow2</name> <capacity>1073741824</capacity> <target> <format type='qcow2'/> <features> <lazy_refcounts/> </features> </target> </volume> and pass this XML to virsh vol-create > It is possible to create a new volume using qcow2 version 3 (compat=1.1) > format *using libvirt/virsh* (I know I can do that via qemu-img)? Any > drawback on using version 3 format? The only drawback is OS compatibility. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :| _______________________________________________ libvirt-users mailing list libvirt-users@redhat.com https://www.redhat.com/mailman/listinfo/libvirt-users