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Re: [Xen-users] migrate from physical disk problems in xen

Paul Stimpson <paul@xxxxxxxxxxxxxxxxxxxx> wrote:

>Hi Adam,
>On 18/01/13 18:31, Adam Goryachev wrote:
>> I've been trying to migrate a win nt 4 machine to a xen domu for the
>past few months with no success. However, on my current attempt, the
>original hardware no longer boots, so I'm trying to resolve the issues
>with xen properly, or else take a long holiday...
>On one of our Windows XP installs in a far off place, we found that the
>HAL that shipped on our Windows disc wasn't virtualisation-friendly. 
>This was on VMWare (not Xen) so it may not apply but we had to get a 
>special version of XP with a different HAL.

It isn't the HAL, since the OS boots up, I've had HAL problems before (can be 
fixed by tweaking the xen config file usually)...

>> Anyway, the physical machine had a 9G drive (OS drive), a 147 G drive
>(not in use) and a 300G drive (all SCSI Ultra320 on the same SCSI
> From here on it, I will call the 9GB drive "sda", the 147GB "sdb" and 
>the 300GB "sdc" - Please adjust anything I say if your system is
>> Everytime, I've booted linux, used dd to image the original 2 drives
>(ignored the 147G drive), and written each image with dd to an LV
>Are you dd-ing the Windows partition or the whole drive into the 
>container file? I think you will get better results with the whole

I did something like this:
dd if=/dev/sda of=/mnt/sda.img bs=8M
dd if=/dev/sdc of=/mnt/sdc.img bs=8M
Then, I moved /mnt drive to another machine and did:
dd if=/mnt/sda.img of=/dev/vg0/machine_d1 bs=8M
dd if=/mnt/sdc.img of=/dev/vg0/machine_d2 bs=8M

>> This is exported by iscsi to xen
>> The c: works fine, and I can boot properly in VGA mode (safe mode)
>but the 300G drive always shows as corrupt. I've now upgraded to
>win2000 in the VM, and win2000 reports the drive as healthy (hardware)
>but blank with no filesystem on it.
>What are you passing to the VM in the "disk=[]" line please?

disk = [ 
'file:/mnt/blah.iso:ioemu:hdc:cdrom,r' ]

>Whatever you pass will be interpreted by Windows as a raw drive, so it 
>can't just be a partition, it has to have a partition table and MBR
>If you just pass a partition, you are likely to see some strange 
>partitioning arrangement in Windows Disk management (random size 
>partitions/free space chunks) and, in the file manager, you will see no
>The disk line should probably pass sdc, rather than sdc1, or you need
>to make a partition table and a partition in it using parted.

Yep, I'm copying the entire drive, and windows does actually see the partition 
table correctly (as does linux from the domu and dom0).

>> However, on the xen machine, I can use fdisk to see the partition
>table, kpartx -a to add the partition device in /dev/mapper, and I can
>even mount the drive in Linux and see all of it's contents.
>I would recommend you don't use fdisk in Linux on this kind of task. 
>Fdisk has a nasty habit of imposing its own default CHS geometry on 
>disks. Like, the other day, it told me the appropriate start sector for
>the first partition on my virtual disc was 2048 when it really should 
>have been 63). This can lead to things not matching and may be stopping
>your VM from mounting the machine.

I didn't use fdisk to create or modify anything, just fdisk -l to view the 
partition table....

>> I suspect the problem is the way windows translates the CHS values of
>the drive, and so can't see things the same way that NT could on the
>physical hardware.
>May well be due to what Linux fdisk did... I would recommend you try 
>parted instead.
>> I'm at a complete loss on how to resolve this issue, or what to
>try/look at. If all else fails I figured to try and create a new 300G
>drive, format it from win2k, and then somehow transfer the files from
>Linux into win2k, without losing any of the permissions / etc which I
>guess will be somewhat challenging.

Thanks for your response, I am fairly sure it isn't a partition issue though. 
If you have any other ideas, I'd really appreciate it.


Adam Goryachev
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