[ovirt-users] actual size greater than virtual size?

[Gianluca Cecchi]

On Mon, Feb 20, 2017 at 11:08 PM, Nir Soffer <nsoffer at redhat.com> wrote:

> On Tue, Feb 14, 2017 at 12:07 AM, Gianluca Cecchi <
> gianluca.cecchi at gmail.com> wrote:
>
>> Hello,
>> I'm on 4.1 with 2 FC SAN storage domains and testing live migration of
>> disk.
>>
>> I started with a CentOS 7.3 VM with a thin provisioned disk of 30Gb.
>> It seems that I can see actual disk size in VM--> Snapshots--> Active VM
>> line and the right sub pane.
>> If I remember correctly before the live storage migration the actual size
>> was 16Gb.
>> But after the migration it shows actual size greater than virtual (33Gb)??
>>
>
> Hi Gianluca,
>
> This is possible for thin disks.
>
> With thin disk we have some overhead for qcow2 metadata, which can be
> up to 10% in the worst case. So when doing operations on thin disk, we
> may enlarge it to the virtual size * 1.1, which is 33G for 30G disk.
>
> Can you share the output of this commands?
>
> (If the vm is running, you should skip the lvchange commands)
>
> lvchange -ay 5ed04196-87f1-480e-9fee-9dd450a3b53b/9af3574d-dc83-485f-
> b906-0970ad09b660he
>
> qemu-img check /dev/5ed04196-87f1-480e-9fee-9dd450a3b53b/9af3574d-dc83-
> 485f-b906-0970ad09b660he
>
> lvchange -an 5ed04196-87f1-480e-9fee-9dd450a3b53b/9af3574d-dc83-485f-
> b906-0970ad09b660he
>
> Nir
>
>
>>
>>
Yes, the VM is active.
In this moment the disk name seems to be without the final "he" letters....

[root at ovmsrv07 ~]# qemu-img check
/dev/5ed04196-87f1-480e-9fee-9dd450a3b53b/9af3574d-dc83-485f-b906-0970ad09b660

No errors were found on the image.
41734/491520 = 8.49% allocated, 3.86% fragmented, 0.00% compressed clusters
Image end offset: 2736128000
[root at ovmsrv07 ~]#
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