[Qemu-devel] snapshots

[Qemu-devel] snapshots

[Pascal Terjan]

hello,
qemu has -loadvm and -snapshot but I don't like having to take care of
using the right vm dump with the snapshot, and having to think to
savevm to the right file when I commit the disk.

What do you think of snapshot/commit (or an additionnal equivalent
command) working with full state ?

[Qemu-devel] snapshots

[chandra shekar]

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hi,everyone i want to change the default location of qemu to store
snapshots.
I have searched savem.c file completely and i am unable to find where does
qemu stores snapshots
and the relevant code for it plz help anyone,thanks

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Re: [Qemu-devel] snapshots

[edison]

QCOW2 snapshots are stored inside the disk image, which is the kind of
internal snapshot.
I had send out a patch
(http://lists.nongnu.org/archive/html/qemu-devel/2010-09/msg01662.html)
last weeks, that can copy the snapshot out of the disk. FYI.

On Sun, Sep 26, 2010 at 10:47 PM, chandra shekar
<chandrashekar512@gmail.com> wrote:
> hi,everyone i want to change the default location of qemu to store
> snapshots.
> I have searched savem.c file completely and i am unable to find where does
> qemu stores snapshots
> and the relevant code for it plz help anyone,thanks
>
>

[Qemu-devel] snapshots

[chandra shekar]

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i have installed the patch
http://lists.nongnu.org/archive/html/qemu-devel/2010-09/msg01662.html<http://lists.nongnu.org/archive/html/qemu-devel/2010-09/msg01662.html,thanks>and
do i need to compile qemu
again and how to use this patch that is what options and command i may use
in the qemu monitor to use this patch,thanks

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Re: [Qemu-devel] snapshots

[Mulyadi Santosa]

Hi...

On Mon, Oct 4, 2010 at 11:56, chandra shekar <chandrashekar512@gmail.com> wrote:
> i have installed the patch
> http://lists.nongnu.org/archive/html/qemu-devel/2010-09/msg01662.html and do
> i need to compile qemu
> again and how to use this patch that is what options and command i may use
> in the qemu monitor to use this patch,thanks
>

Haven't tried it by myself, but I am quite sure you need to recompile
the whole binaries (qemu, qemu-img and so on). Just to be safe...

And as how to use it:
1. do snapshot e.g using "savevm" command in qemu monitor

2. I think it's better to shutdown the guest first to prevent in
flight disk I/O during snapshot copy, then execute:
qemu-img convert -f qcow2 -O qcow2 -s snapshot_name src_img bck_img
where:
-s is the snapshot name of the result image. This will contain ONLY
your snapshots...

src_img_bck_img: your current disk image filename which contains your snapshot.

-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

[Qemu-devel] snapshots

[chandra shekar]

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Hi,everyone i have applied this  patch
http://lists.nongnu.org/archive/html/qemu-devel/2010-09/msg01662.html  to
qemu source and compiled my qemu source and now i like to
bring the snapshot out of the image file so i used


qemu-img convert -f qcow2 -O qcow2 -s one guest1.img
where:

one -> is the snapshot i created in guest1.img and guest1.img contains
windows xp

 but i get an error

*convert: invalid option -- 's'
qemu-img: Could not open 'one'*

please someone help ,thanks

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Re: [Qemu-devel] snapshots

[Stefan Hajnoczi]

On Tue, Oct 12, 2010 at 10:13 AM, chandra shekar
<chandrashekar512@gmail.com> wrote:
>
> Hi,everyone i have applied this  patch
> http://lists.nongnu.org/archive/html/qemu-devel/2010-09/msg01662.html  to
> qemu source and compiled my qemu source and now i like to
> bring the snapshot out of the image file so i used
>
>
> qemu-img convert -f qcow2 -O qcow2 -s one guest1.img
> where:
>
> one -> is the snapshot i created in guest1.img and guest1.img contains
> windows xp
>
>  but i get an error
>
> convert: invalid option -- 's'
> qemu-img: Could not open 'one'

Looks like you used your system qemu-img tool which is not compiled
with the patch.  Make sure to use the patched binary (./qemu-img).

Stefan

[Qemu-devel] snapshots

[chandra shekar]

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i still get a error message  invalid option -- 's'
when using the command
./qemu-img convert -f qcow2 -O qcow2 -s firstsnapshot guest1.img

which i used after applying the patch
http://lists.nongnu.org/archive/html/qemu-devel/2010-09/msg01663.html

but after using
cd qemu
./configure --prefix=/usr --target-list=x86_64-softmmu
make

there is the same error
invalid option -s
plz someone help i am struck at this and my project is not going
forward,thanks

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Re: [Qemu-devel] snapshots

[Mulyadi Santosa]

On Thu, Oct 14, 2010 at 17:22, chandra shekar
<chandrashekar512@gmail.com> wrote:
> i still get a error message  invalid option -- 's'

are you sure the patch applied cleanly? And are you sure you're
rebuilding from scratch?


> plz someone help i am struck at this and my project is not going
> forward,thanks

So touching... do you consider to donate some money then? And next
time, please use proper language. Plz is english slang.... and here
it's not bronx.


-- 
regards,

Mulyadi Santosa
Freelance Linux trainer and consultant

blog: the-hydra.blogspot.com
training: mulyaditraining.blogspot.com

[Qemu-devel] snapshots

[chandra shekar]

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hi everyone i have got snapshot out of the image file now i would like to
analyze the snapshot
like opening it or identifying the fields in it can anyone suggest any
softwares which i can use
to open the snapshot analyze it,thanks

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Re: [Qemu-devel] snapshots

[Stefan Hajnoczi]

On Fri, Jan 7, 2011 at 4:37 AM, chandra shekar
<chandrashekar512@gmail.com> wrote:
> hi everyone i have got snapshot out of the image file now i would like to
> analyze the snapshot
> like opening it or identifying the fields in it can anyone suggest any
> softwares which i can use
> to open the snapshot analyze it,thanks

I'm not sure what format your snapshot data is in.  What exactly did you do?

qemu-img and qemu-io can be used to manipulate image data.

Check what format the data is in:
qemu-img info <snapshot-file>

Read first sector (for debugging):
qemu-io -c 'read -v 0 512' <snapshot-file>

Convert to raw image (suitable for dd, fdisk, hex editor, etc):
qemu-img convert <snapshot-file> raw-data.img

If you want to inspect savevm data (saved device state) then you're on
your own.  AFAIK there isn't an external tool to dissect it.  It would
be quickest to add some code into QEMU to dump out the info you need.

Stefan