Re: driver type raw-xz supports discard=unmap?

[Chris Murphy]

On Mon, Jul 25, 2022, at 5:13 AM, Daniel P. Berrangé wrote:
> On Fri, Jul 22, 2022 at 04:03:52PM -0400, Chris Murphy wrote:
>> Is this valid?
>> 
>> `<disk device="disk" type="file">
>> <target dev="vda" bus="virtio"/>
>> <source file="Fedora-Workstation-Rawhide-20220721.n.0.aarch64.raw-xz"/>
>> <driver name="qemu" type="raw-xz" discard="unmap"/>`
>> `/>
>> </disk>`
>> 
>> I know type="raw" works fine, I'm wondering if there'd be any problem
>> with type "raw-xz" combined with discards?
>
> This is libvirt configuration, so libvirt-users@redhat.com is the better
> list in general. That said, what is this 'raw-xz' type you refer to ?
>
> AFAIK, that is not a disk driver type that exists in either libvirt or
> QEMU releases.

Huh, interesting. I have no idea then. I just happened to notice it in the 
(libvirt) XML config that's used by oz.
https://kojipkgs.fedoraproject.org//packages/Fedora-Workstation/Rawhide/20220721.n.0/images/libvirt-raw-xz-aarch64.xml

When manually modifying a virt-manager created config, to change "raw" to 
"raw-xz" I get an error:

# virsh edit uefivm
error: XML document failed to validate against schema: Unable to validate doc 
against /usr/share/libvirt/schemas/domain.rng
Extra element devices in interleave
Element domain failed to validate content

Failed. Try again? [y,n,i,f,?]: 

I've got no idea what happens if an invalid type is specified in the config. 
The VM's are definitely running despite this. I'll ask oz devs.