[libvirt-users] unknown driver format value 'qcow3'

[Dominique Ramaekers]

According to the qcow3 roadmap http://wiki.qemu.org/Features/Qcow3 , qcow3 is an extention of qcow2 and you should be able to use the existing qcow3 images as qcow2 images. So changing qcow3 to qcow2 in you XML should fix this.

-----Oorspronkelijk bericht-----
Van: Eric Blake [mailto:eblake at redhat.com] 
Verzonden: woensdag 15 april 2015 16:20
Aan: Jatin Davey; libvirt-users at redhat.com
Onderwerp: Re: [libvirt-users] unknown driver format value 'qcow3'

On 04/15/2015 08:13 AM, Jatin Davey wrote:
> Hi All
> 
> I am trying to deploy VMs using libvirt and a domainXML file where i 
> mention the parameters for the VM to be deployed.
> 
> I am using libvirt version: libvirt 0.10.2

[I'm guessing that you are using something based on RHEL 6, based on how old that version number is...]

This version of libvirt does not know how to handle qcow2v3 files.  qemu started creating these by default around qemu 2.0 or so, but you can still manually create older qcow2v2 files by specifying:

qemu-img create -o compat=0.10 -f qcow2 ...

whenever you are manually creating images.

> 
> Do i need to upgrade to any specific version of libvirt ? or change 
> any file to make this work ?

With new enough qemu-img, you can also downgrade an image in-place:

qemu-img convert -f qcow2 -o compat=0.10 file

Or, as you guessed, you can upgrade to newer libvirt that understands the newer format.  [For example, basing your distro on RHEL 7, even if you choose to use CentOS instead of RHEL, is a way to get new-enough libvirt]

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

_______________________________________________
libvirt-users mailing list
libvirt-users at redhat.com
https://www.redhat.com/mailman/listinfo/libvirt-users