[Qemu-devel] Disk images

[Qemu-devel] Disk images

[Julien Lancien]

Hi,

The user forum seems to have been down for a while, so I post my
question to this mailing list.

The -smd dir option allows the emulated machine to access the external
world. I was wondering if there was a way to do it the other way:
allow the host to access the disk image of the emulated machine.

My problem is that I used virtual machine to prepare various flavor of
Linux (installation, configuration), and I'ld like to make a tar image
of the files once I'm finished. Currently, I boot a live cd inside the
virtual machine, mount the smb dir, and then make the transfer. But it
is damn slow ! Maybe there is way to get the data from the disk image
directly ?

A related question: which disk format offer the best performances ? I
don't care much about space, but I'ld like to use some of the virtual
machines as regular machines and not just for test.

Talking about disk images, is there some way to defragment them ? I
mean after a while, being used a lot, they probably get fragmented too
(inside the disk image, not the file of the disk image).

And finally my last question: imagine I create a big file in my
virtual OS, and then delete it, the size of the disk image won't
shrink. I guess that there are some filesystem issues there, but more
generally, can a disk image shrink eventually ?

Thanks for any tip, advice or help.

[Qemu-devel] Re: Disk images

[Julien Lancien]

> The -smd dir option allows the emulated machine to access the external
> world. I was wondering if there was a way to do it the other way:
> allow the host to access the disk image of the emulated machine.
>
> My problem is that I used virtual machine to prepare various flavor of
> Linux (installation, configuration), and I'ld like to make a tar image
> of the files once I'm finished. Currently, I boot a live cd inside the
> virtual machine, mount the smb dir, and then make the transfer. But it
> is damn slow ! Maybe there is way to get the data from the disk image
> directly ?

Ok, found the answer for this one here:
http://wiki.archlinux.org/index.php/Qemu.

Sorry, I should have searched before.

> A related question: which disk format offer the best performances ? I
> don't care much about space, but I'ld like to use some of the virtual
> machines as regular machines and not just for test.
>
> Talking about disk images, is there some way to defragment them ? I
> mean after a while, being used a lot, they probably get fragmented too
> (inside the disk image, not the file of the disk image).
>
> And finally my last question: imagine I create a big file in my
> virtual OS, and then delete it, the size of the disk image won't
> shrink. I guess that there are some filesystem issues there, but more
> generally, can a disk image shrink eventually ?

Re: [Qemu-devel] Disk images

[Henning Sprang]

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Hi Julien

On Wed, 2005-11-02 at 14:02 -0500, Julien Lancien wrote:
> Hi,
> 
> The user forum seems to have been down for a while, so I post my
> question to this mailing list.

The user forum has moved to http://qemu.dad-answers.com, but it looks
like user questions are allowed here.

Henning

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