On Tue, May 01, 2018 at 12:35:05PM +0200, Gianluca Cecchi wrote:
On Tue, May 1, 2018 at 10:45 AM, Daniel P. Berrangé <berrange@redhat.com> wrote:
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.
BTW: in virt-manager of CentOS 7.4 by default qcow2 disks (see below for zzz3.qcow2) are created with compatibility 1.1 (probably indirectly because of its lazy refcounts feature enabled, as Daniel wrote):
Yes, virt-manager explicitly turns on lazy refcounts if it sees a new enough QEMU, so will get v3 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 :|