[Qemu-devel] qemu and already installed OS

[Qemu-devel] qemu and already installed OS

[vaise]

I used dd on a working partition, created a file and lauched qme...
dd if=/dev/hda1 of=/home/me/partitionhda.img
but the boot fails :
Disk I/O error
Replace the disk, and then prees any key

should I have added some extra options to dd ? (like bs= count= ?)
 Did it work for you ?

Re: [Qemu-devel] qemu and already installed OS

[Thomas Glanzmann]

Hi,

> dd if=/dev/hda1 of=/home/me/partitionhda.img

In order to boot from this you need a boot sector (partitiontable).

Which means you have to a dd if=/dev/hda of=/path/to/img
                                     ~~~ -> without the appended '1'

> should I have added some extra options to dd ? (like bs= count= ?)

Specifying a bigger blocksize could speedup things but don't specifying
one shouldn't do any harm but killing your time. :-)

	Thomas

Re: [Qemu-devel] qemu and already installed OS

[vaise]

On Friday 19 March 2004 11:11, Thomas Glanzmann wrote:
> In order to boot from this you need a boot sector (partitiontable).
> Which means you have to a dd if=/dev/hda of=/path/to/img
>                                      ~~~ -> without the appended '1'
Good, good !
It means that I have to copy the whole disk, or approximatively a file bigger 
than my partition.
Of course there must be some tools to save only the boot sector and the 
partition wanted.
But I don't need to do a very clean job today, so that should be perfect for 
this time.
thank you Thomas.

Re: [Qemu-devel] qemu and already installed OS

[vaise]

On Friday 19 March 2004 12:46, vaise@votreservice.com wrote:
> On Friday 19 March 2004 11:11, Thomas Glanzmann wrote:
> > In order to boot from this you need a boot sector (partitiontable).
> > Which means you have to a dd if=/dev/hda of=/path/to/img
> >                                      ~~~ -> without the appended '1'
> It means that I have to copy the whole disk, or approximatively a file
> bigger than my partition.
dd if=/dev/hda of=/home/me/disk.img bs=1024 count=1600000
It does not boot either...
the only message is "L"
I must be wrong somewhere...

Re: [Qemu-devel] qemu and already installed OS

[Rudi Lippert]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Friday 19 March 2004 14:24, vaise@votreservice.com wrote:
> the only message is "L"
> I must be wrong somewhere...

what are you complaining about? most programs give you one letter less than 
that in case of an error ;o)
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Version: GnuPG v1.2.4 (GNU/Linux)

iD8DBQFAWuvj1nTg39QS/TsRAlLeAJ0Ya79ACiCH6DN4vgJ6LpASEycglwCfUxin
hq/2MnveUCSbQ6xyFJzErEk=
=KY4J
-----END PGP SIGNATURE-----

Re: [Qemu-devel] qemu and already installed OS

[Thomas Glanzmann]

Hi,

> dd if=/dev/hda of=/home/me/disk.img bs=1024 count=1600000
                                              ~~~~~~~~~~~~~
drop that count parameter.

	Thomas

Re: [Qemu-devel] qemu and already installed OS

[vaise]

On Friday 19 March 2004 13:12, Thomas Glanzmann wrote:
> > dd if=/dev/hda of=/home/me/disk.img bs=1024 count=1600000
> drop that count parameter.
It means I will save my whole (and only) hard disk ? ?

Re: [Qemu-devel] qemu and already installed OS

[vaise]

On Saturday 20 March 2004 10:09, vaise@votreservice.com wrote:
> On Friday 19 March 2004 13:12, Thomas Glanzmann wrote:
> > > dd if=/dev/hda of=/home/me/disk.img bs=1024 count=1600000
> >
> > drop that count parameter.
>
> It means I will save my whole (and only) hard disk ? ?
>
Thomas, you were right !
In order to copy the partition with dd, and to manage to boot, we have to 
copy :
-the boot sector (if=/dev/hda and not if=/dev/hda1)
-the target partition for qemu (of course)
-AND the linux partition where grub comes from.

I managed to store these 3 things in the begining of the hard disk, so it 
takes me only 2.5Gb. correct.

[Qemu-devel] Re: qemu and already installed OS

[Sami Haahtinen]

vaise@votreservice.com wrote:
> dd if=/dev/hda of=/home/me/disk.img bs=1024 count=1600000
> It does not boot either...
> the only message is "L"
> I must be wrong somewhere...

That would be your lilo, grab the kernel from the partition, put it 
somewhere, load that kernel image with qemu (with the appropriate 
parameters, you can get them from lilo conf, it's the append line) and 
fire away.

once you get it to boot, reinstall lilo.

i can't really tell you the commands how to do this, as i'm not at home 
to check them.

Regards, Sami

Re: [Qemu-devel] Re: qemu and already installed OS

[vaise]

On Friday 19 March 2004 14:17, Sami Haahtinen wrote:
> > dd if=/dev/hda of=/home/me/disk.img bs=1024 count=1600000
> > It does not boot either...
> > the only message is "L"
> > I must be wrong somewhere...
>
> That would be your lilo, grab the kernel from the partition, put it
> somewhere, load that kernel image with qemu (with the appropriate
> parameters, you can get them from lilo conf, it's the append line) and
> fire away.
>
How do you "grab the kernel" ?
I tried "dd if=/dev/hda", but as I said, lilo crash....

[Qemu-devel] Re: qemu and already installed OS

[Sami Haahtinen]

vaise@votreservice.com wrote:
> On Friday 19 March 2004 14:17, Sami Haahtinen wrote:
>>That would be your lilo, grab the kernel from the partition, put it
>>somewhere, load that kernel image with qemu (with the appropriate
>>parameters, you can get them from lilo conf, it's the append line) and
>>fire away.
>>
> 
> How do you "grab the kernel" ?
> I tried "dd if=/dev/hda", but as I said, lilo crash....

Ok, i found a neater way for you to do that.. ;)

go to: http://www.lnx-bbc.org/download.html fetch the iso image.

boot with the image, log in as root. mount your partition, and chroot to it:
mount /dev/hda1 /tmp
chroot /tmp /bin/sh

If you have other filesystems you are forced to mount, you shouldn't 
really do this unless you have to. If you do this, you need to clean up 
before you go:
mount -a

Re-install lilo by running lilo.

Back out once again:
exit (exit back to lnx-bbc)
umount /tmp
sync (i like to play it safe)

shutdown the system and boot up without the bootable CD-Image.

That's the quick tour on recovering from a HD failure, there are better 
howtos for this, but if you are clever you should be able to do it with 
this.

-- Sami

[Qemu-devel] [small help] dd, mbr, fdisk

[Sebastien Bechet]

where myhdsize is your harddisk size in Mo :

HDS = myhdsize / 512
$ dd if=/dev/zero of=virtualhardisk.hd bs=2048 count=HDS
$ install-mbr virtualhardisk.hd # apt-get install mbr ...
$ cfdisk virtualhardisk.hd

[Do what you want with your hard disk & qemu ...]

Then you can use (for your "hda1") :
losetup -o 32256 /dev/loop0 virtualhardisk.hd
mount /dev/loop0 /mnt/temp
[...]
umount /mnt/temp
losetup -d /dev/loop0

Bye.

-- 
Sebastien Bechet <s.bechet@av7.net>
av7.net