[Users] Live storage migration snapshot removal (fails)

[Sander Grendelman]

I can open a bug on this.

Should I file it for the entire "snapshot removal fails"-problem or
just this error?


I've looked at the parsing error and the problem seems to be that the
qemuImg.check() function expects a qemu-img version that outputs a
string like: "Image end offset: 262144".

The only version I could find that does that is the one in the F19 virt-preview
repository. Stock F19 qemu-img doesn't have this output. Nor do the stock EL6
or qemu-img-rhev EL6 versions.

The only function that calls qemuImg.check is blockVolume.shrinkToOptimalSize()
this function needs (and uses) the parsed offset to shrink the LV containing the
qcow2 image.

On Fri, Nov 8, 2013 at 4:33 PM, Federico Simoncelli <fsimonce at redhat.com> wrote:
> ----- Original Message -----
>> From: "Dan Kenigsberg" <danken at redhat.com>
>> To: "Sander Grendelman" <sander at grendelman.com>
>> Cc: users at ovirt.org, fsimonce at redhat.com, ykaplan at redhat.com
>> Sent: Friday, November 8, 2013 4:06:53 PM
>> Subject: Re: [Users] Live storage migration snapshot removal (fails)
>>
>> On Fri, Nov 08, 2013 at 02:20:39PM +0100, Sander Grendelman wrote:
>>
>> <snip>
>>
>> > 9d4e8a43-4851-42ff-a684-f3d802527cf7/c512267d-ebba-4907-a782-fec9b6c95116
>> > 52178458-1764-4317-b85b-71843054aae9::WARNING::2013-11-08
>> > 14:02:53,772::image::1164::Storage.Image::(merge) Auto shrink after
>> > merge failed
>> > Traceback (most recent call last):
>> >   File "/usr/share/vdsm/storage/image.py", line 1162, in merge
>> >     srcVol.shrinkToOptimalSize()
>> >   File "/usr/share/vdsm/storage/blockVolume.py", line 320, in
>> > shrinkToOptimalSize
>> >     qemuImg.FORMAT.QCOW2)
>> >   File "/usr/lib64/python2.6/site-packages/vdsm/qemuImg.py", line 109, in
>> >   check
>> >     raise QImgError(rc, out, err, "unable to parse qemu-img check output")
>> > QImgError: ecode=0, stdout=['No errors were found on the image.'],
>> > stderr=[], message=unable to parse qemu-img check output
>>
>>
>> I'm not sure that it's the only problem in this flow, but there's a
>> clear bug in lib/vdsm/qemuImg.py's check() function: it fails to parse
>> the output of qemu-img.
>>
>> Would you open a bug on that? I found no open one.
>
> I remember that this was discussed and the agreement was that if the offset
> is not reported by qemu-img we should have used the old method to calculate
> the new volume size.
>
> We'll probably need to verify it. Sander can you open a bug on this?
>
> Thanks,
> --
> Federico