[virt-tools-list] virt-resize: respect sparse files

[Richard W.M. Jones]

On Tue, Jul 06, 2010 at 06:18:44AM -0400, T Johnson wrote:
> Unless I'm doing something wrong, it seems that virt-resize currently
> doesn't notice if the source image is sparse during it's copy process. For
> example, if I have a 5GB sparse image that is really only 1GB in used space,
> and want to grow that image to a 10GB sparse image with virt-resize.. I end
> up with a 10GB sparse image now with 5GB used.

This is correct, and a bug.

> Would it be possible for virt-resize to pay attention to "sparseness" during
> the copy process by default or offer an option to do so?

It is quite a lot more complicated than that to implement ...  I had
in mind a blog posting along these lines, so maybe I will write more
about it soon.

You can file a bug if you want, but TBH it requires changes at all
levels of the virtualization stack (good, sound changes, but invasive
and not on anyone's radar at the moment) and it's not likely to be
fixed any time soon.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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