Libguestfs - Sep 2014 - Why is virt-resize designed to involve two disks?

HI,

As you've known, vhd-util and qemu-img both provide the capacity for
resizing the original disk, but why is virt-resize designed to involve
two disks, not only original disk? Is there any concern? Is it
possible that only one original disk is involved in virt-resize?


-- 
Regards,

Zhi Yong Wu

On Tue, Sep 23, 2014 at 06:19:21PM +0800, Zhi Yong Wu
wrote:
> As you've known, vhd-util and qemu-img both provide the capacity for
> resizing the original disk,
.. although they only resize the container, not the contents which is
what virt-resize does.  So these tools are not really comparable.
> but why is virt-resize designed to involve
> two disks, not only original disk? Is there any concern? Is it
> possible that only one original disk is involved in virt-resize?
I'm guessing this question is why virt-resize doesn't work on disk
images in-place.

This I hope is answered in the FAQ here:

 
http://libguestfs.org/guestfs-faq.1.html#why-doesnt-virt-resize-work-on-the-disk-image-in-place

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
virt-top is 'top' for virtual machines.  Tiny program with many
powerful monitoring features, net stats, disk stats, logging, etc.
http://people.redhat.com/~rjones/virt-top

On Tue, Sep 23, 2014 at 8:11 PM, Richard W.M. Jones <rjones@redhat.com>
wrote:
> On Tue, Sep 23, 2014 at 06:19:21PM +0800, Zhi Yong Wu wrote:
>> As you've known, vhd-util and qemu-img both provide the capacity
for
>> resizing the original disk,
>
> .. although they only resize the container, not the contents which is
> what virt-resize does.  So these tools are not really comparable.
Yes.
>
>> but why is virt-resize designed to involve
>> two disks, not only original disk? Is there any concern? Is it
>> possible that only one original disk is involved in virt-resize?
>
> I'm guessing this question is why virt-resize doesn't work on disk
> images in-place.
>
> This I hope is answered in the FAQ here:
>
>  
http://libguestfs.org/guestfs-faq.1.html#why-doesnt-virt-resize-work-on-the-disk-image-in-place
It is really what i want, thanks.
>
> Rich.
>
> --
> Richard Jones, Virtualization Group, Red Hat
http://people.redhat.com/~rjones
> Read my programming and virtualization blog: http://rwmj.wordpress.com
> virt-top is 'top' for virtual machines.  Tiny program with many
> powerful monitoring features, net stats, disk stats, logging, etc.
> http://people.redhat.com/~rjones/virt-top


-- 
Regards,

Zhi Yong Wu