Bugs item #2490866, was opened at 2009-01-06 23:10
Message generated for change (Comment added) made by thekozmo
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=893831&aid=2490866&group_id=180599

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: qemu
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Adrian Bridgett (abridgett)
Assigned to: Nobody/Anonymous (nobody)
Summary: repeatable corruption with qcow2 on kvm-79

Initial Comment:
Creating a qcow2 image, mkfs.ext3, sometimes mounting it would fail 
immediately, but in all cases it would corrupt (overwritten with zeros) after 
starting up backuppc on it.   This is KVM-79 on a Debian lenny host and guest.

This occured using virtio or not.  Swapping to a raw file or LV worked 
flawlessly.  I've tested the box with memtest and I don't have issues elsewhere 
but I've seen corruptions on other images.  host and guest are both 
2.6.26-1-adm64 kernel (debian lenny) I'm running 32-bit userspace everywhere.  
Dual core Intel Core2 E6300.

I see KVM-81 has "improve qcow2 data integrity with cache=writethrough" which 
_might_ be what I'm hitting - but I can't find more details about this to check 
(and backport patch to debian package or wait for newer debian package).

thanks.

----------------------------------------------------------------------

Comment By: Dor Laor (thekozmo)
Date: 2009-01-13 10:23

Message:
danv, can you please specify more details - does this corruption is
consistent or happens rarely?
Do you create/manage snapshots while the image is up?
If no special snapshot action taken, what's the guest do between the boot
and the shutdown?
(Just to make sure, you do not run multiple guests with the same image
right?)

----------------------------------------------------------------------

Comment By: Daniel van Vugt (danv)
Date: 2009-01-13 09:48

Message:
Confirmed on kvm-82. I am getting reproducible qcow2 corruption on my
Windows images.

Host: Ubuntu 8.04.1 amd64   (Intel(R) Core(TM)2 Quad CPU    Q6600  @
2.40GHz)
Guest: Multiple (see below)

Summary is:
1. Boot working Windows image (qcow2)
2. Use Windows and then shut down the VM cleanly.
3. Image file is now corrupt and unusable. Won't boot again and qemu-img
reports invalid information.

Confirmed with multiple Windows Server 2003 guests and now Windows 7 beta
too:

$ qemu-img info windows7beta.qcow2
image: windows7beta.qcow2
file format: qcow2
virtual size: 20G (21474836480 bytes)
disk size: 5.0G
cluster_size: 4096
Snapshot list:
ID        TAG                 VM SIZE                DATE       VM CLOCK
1         Fresh_install          1.3M 2009-01-09 15:34:31   00:00:00.000
2         Activated_kvm-82       1.3M 2009-01-09 15:43:27   00:00:00.000

$ qemu -m 512 -usbdevice tablet -redir tcp:3389::3389 windows7beta.qcow2
&
(use and then shut down windows)

$ qemu-img info windows7beta.qcow2
image: windows7beta.qcow2
file format: raw   <---------------------------- INVALID
virtual size: 5.0G (5353566208 bytes) <--------- INVALID
disk size: 5.0G

$ qemu -m 512 -usbdevice tablet -redir tcp:3389::3389 windows7beta.qcow2
-S &
(qemu) info snapshots
Snapshot devices: ide0-hd0
bdrv_snapshot_list: error -95



----------------------------------------------------------------------

Comment By: roy anonymous (roy-anonymous)
Date: 2009-01-07 19:14

Message:
I am not quite sure it's true or not, for my case, I get corruption if I
have a new FC9 Guest installation with qcow2 with virtio_blk. But it won't
have any problem if I install with a FC8 qcow2 installation, then upgrade
to FC9 with virtio_blk

----------------------------------------------------------------------

Comment By: Laszlo Dvornik (ldvornik)
Date: 2009-01-07 09:42

Message:
Same problem here.

With Lenny and vanilla 2.6.28 kernel, with KVM 79, and with KVM 82 user
tools.
Tried with KVM 82 module compile for 2.6.28 and with 2.6.28 builtin KVM
sources.
32-bit userspace and kernel, Intel C2D T7100.

Another effect:
With empty qcow2, vmdk disk image formats, when I try to create a
partition and save the new partition table, they can't save it until
reboot. With raw image format there is no such problem.

I liked to try with qcow, but:
qemu: could not open disk image teszt.qcow

I switched all of my disk images to raw, until the problem fixed.

PS: The host filesystem is ext4, but I tested under ext3 filesystem too
and the problem wasn't disappeared.

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=893831&aid=2490866&group_id=180599
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to