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From Marcus Sorensen <shadow...@gmail.com>
Subject Re: qemu-img convert a qcow2 to a qcow2
Date Wed, 05 Dec 2012 21:00:34 GMT
Eventually we'll probably want to support multiple versions, replacing one
or both of the formats with variables, but even then we'll probably just
want to copy if source format == destination format.


On Wed, Dec 5, 2012 at 1:51 PM, Rohit Yadav <rohit.yadav@citrix.com> wrote:

>
> On 05-Dec-2012, at 12:17 PM, Marcus Sorensen <shadowsor@gmail.com> wrote:
>
> > Anyone know why we do a convert from qcow2 to qcow2 when we crete a
> volume
> > or template? It seems slower than file copy, and it strips valuable
> > compression which could speed up deployments significantly. Our qcow2
> > templates are compressed to about 1/3 size of uncompressed, and since the
> > compression is read-only it doesn't really affect future write
> performance,
> > and gives a slight performance gain to reads since less is read.
> >
> > createvolume.sh
> > qemu_img convert -f qcow2 -O qcow2
> >
> > managesnapshot.sh
> > qemu_img convert -f qcow2 -O qcow2
> >
> > createtmplt.sh
> > qemu_img convert -f qcow2 -O qcow2
> >
> > I'd suggest if we already know it's qcow2, and we want to create a qcow2
> to
> > copy the file. Objections?
>
>
> I don't know why we do that, but what the command is saying is that we
> want to convert an input image from qcow2 to keeping the same output
> format, -O qcow2
> But yes, if the input format is already qcow2 and output is qcow2 we can
> just copy the file. Edison?
>
> Regards.

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