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Re: [Qemu-devel] qcow2 corrupted image, no error from qemu-img check
From: |
Stefan Hajnoczi |
Subject: |
Re: [Qemu-devel] qcow2 corrupted image, no error from qemu-img check |
Date: |
Mon, 3 Oct 2011 08:51:47 +0100 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Fri, Sep 30, 2011 at 09:21:29PM +0200, nicolas prochazka wrote:
> qemu-img from qemu 0.15
>
> DEV-10.98.98.1:~# qemu-img info /mnt/disks/export/images/vm_import
> image: /mnt/disks/export/images/vm_import
> file format: qcow2
> virtual size: 20G (21474836480 bytes)
> disk size: 12G
> cluster_size: 65536
>
>
> DEV-10.98.98.1:~# qemu-img check
> /mnt/disks/export/images/vm_import_1317298935151
> No errors were found on the image.
>
> DEV-10.98.98.1:~# qemu-img convert -O qcow2
> /mnt/disks/export/images/vm_import /mnt/disks/export-ns/TEST.qcow2
> qemu-img: error while reading sector 5406720: Input/output error
You can check whether this error is reproducible using qemu-io(1):
~/qemu$ ./qemu-io -c "read -v $((5406720 * 512)) 65536"
/mnt/disks/export/images/vm_import
This command should hexdump the cluster at 5406720 sectors. If this
fails in the same way it will be easier to debug this command than
running a full qemu-img convert each time and waiting for it to fail.
Another useful bit of information:
~/qemu$ ./qemu-io -c "map" /mnt/disks/export/images/vm_import
This prints out the guest -> image file cluster mapping and can be
useful in understanding if/how the file is corrupted.
Also, have you tried copying the qcow2 file just using cp(1)? It's
worth checking that cp(1) succeeds and there isn't a real I/O Error
(typically you would also see errors in dmesg).
Stefan
- Re: [Qemu-devel] qcow2 corrupted image, no error from qemu-img check,
Stefan Hajnoczi <=