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Re: [Qemu-devel] Re: block: format vs. protocol, and how they stack
From: |
Daniel P. Berrange |
Subject: |
Re: [Qemu-devel] Re: block: format vs. protocol, and how they stack |
Date: |
Tue, 22 Jun 2010 17:56:33 +0100 |
User-agent: |
Mutt/1.4.1i |
On Tue, Jun 22, 2010 at 05:40:02PM +0100, Jamie Lokier wrote:
> Kevin Wolf wrote:
> > > The "protocol" parlance breaks down when we move away from the simple
> > > stuff. For instance, qcow2 needs two children: the block driver
> > > providing the delta bits (in qcow2 format), and the block driver
> > > providing the base bits (whose configuration happens to be stored in the
> > > delta bits).
> >
> > Backing files are different. When talking about opening images (which is
> > what we do here) the main difference is that they can be opened only
> > after the image itself has been opened. I don't think we should include
> > them in this discussion.
>
> Imho, being unable to override the qcow2 backing file from the command
> line / monitor is very annoying, if you've moved files from another
> machine or just renamed them for tidiness. It's especially bad if the
> supplied qcow2 file has an absolute path in it, quite bad if it has
> subdirectories or ".." components, annoying if you've been given
> several qcow2 files all of which have the name "backing-file" stored
> in them which are different images because they were originally on
> different machines, and awful if it has the name of a block device in it.
FYI, in the scenario where you've moved backing files around, you can
use qemu-img to update the location
qemu-img rebase -u -b /path/to/newbackingfile.img demo.img
Regards,
Daniel
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- Re: [Qemu-devel] Re: block: format vs. protocol, and how they stack, (continued)
- Re: [Qemu-devel] Re: block: format vs. protocol, and how they stack, Christoph Hellwig, 2010/06/28
- Re: [Qemu-devel] Re: block: format vs. protocol, and how they stack, Jamie Lokier, 2010/06/22
- [Qemu-devel] Re: block: format vs. protocol, and how they stack, Anthony Liguori, 2010/06/21
- [Qemu-devel] Re: block: format vs. protocol, and how they stack, Kevin Wolf, 2010/06/22
- [Qemu-devel] Re: block: format vs. protocol, and how they stack, Anthony Liguori, 2010/06/22
- [Qemu-devel] Re: block: format vs. protocol, and how they stack, Kevin Wolf, 2010/06/22
- [Qemu-devel] Re: block: format vs. protocol, and how they stack, Anthony Liguori, 2010/06/22
- [Qemu-devel] Re: block: format vs. protocol, and how they stack, Markus Armbruster, 2010/06/21
- [Qemu-devel] Re: block: format vs. protocol, and how they stack, Kevin Wolf, 2010/06/22
- Re: [Qemu-devel] Re: block: format vs. protocol, and how they stack, Jamie Lokier, 2010/06/22
- Re: [Qemu-devel] Re: block: format vs. protocol, and how they stack,
Daniel P. Berrange <=