[virt-tools-list] Storage image files and permissions

[Eric Blake]

On 11/27/18 9:23 AM, Joachim Wagner wrote:
>>>> Moreover, I created a QCOW3 disk image. I asked for a maximum capacity
>>>> of 6GB and initial allocation of 0GB (zero).
>>>> I got a 6GB image file. Is this a bug or am I missing something?
>>
>> Any hint on this?
>> With QCOW2 I used to get a 200KB file as initial image, no matter it's
>> maximum size.
> 
> Have you checked the space used on disk or the file size? Possibly, the
> default on your system is to use sparse pre-allocation when supported by the
> filesystem. Also, did you try preallocation=off or metadata (see man page)?
> 
> How do you request qcow3? According to the edit history of https://
> wiki.qemu.org/Features/Qcow3 , qcow3 should be many years old but the manpage
> of qemu-img on my current system does not mention qcow3.

You probably mean qcow2v3. It is also spelled as 'qemu-img create -o 
compat=1.1' (newer qemu-img also recognizes the spelling compat=v3), as 
opposed to the older 'qemu-img create -o compat=0.10' or v2 images.  But 
if the virt-manager gui is specifically calling it qcow3, rather than 
qcow2v3, then that's a needless confusion that we should fix in the gui.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org