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From Bryan Whitehead <dri...@megahappy.net>
Subject Re: qemu-img convert a qcow2 to a qcow2
Date Fri, 07 Dec 2012 23:51:11 GMT
I'd prefer to see backing qcow2 support instead of any kind of copying.


On Wed, Dec 5, 2012 at 1:29 PM, Edison Su <Edison.su@citrix.com> wrote:

> If the source image has dependence on other images, then we should use
> "qemu-img convert ", otherwise, "cp" is enough.
>
> > -----Original Message-----
> > From: Marcus Sorensen [mailto:shadowsor@gmail.com]
> > Sent: Wednesday, December 05, 2012 1:01 PM
> > To: cloudstack-dev@incubator.apache.org
> > Subject: Re: qemu-img convert a qcow2 to a qcow2
> >
> > 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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