Hello,

Just upping my message.
We have a frequent use of importing libvirt vms with sparsified qcow2 disks, so we have hit the import bug to iSCSI a lot of times already. Is it an unsupported use case?
Same question about moving a raw/sparse disk from NFS volume to iSCSI.

Thanks for any feedback


Guillaume Pavese
Ingénieur Système et Réseau
Interactiv-Group


On Wed, Jul 27, 2022 at 11:45 AM Guillaume Pavese <guillaume.pavese@interactiv-group.com> wrote:
Did anyone have the chance to look at this problem?

It seems that it may be related to another problem we have encountered when trying to import a vm with qcow2 disks that have been sparsified first (virt-sparsify), from a kvm/libvirt provider to a iSCSI storage domain.
In those case, we get an error that the import failed, and in the import log we can see a similar "qemu-img: error while writing at byte xxx: No space left on device"

Obviously, it is not a storage space problem as in both situations we are using an iSCSI LUN with ample free space.

Best regards,

Guillaume Pavese
Ingénieur Système et Réseau
Interactiv-Group


On Thu, Jul 21, 2022 at 11:49 PM Guillaume Pavese <guillaume.pavese@interactiv-group.com> wrote:
On a 4.5.1 DC, I have imported a vm and its disk from an old 4.3 DC (through an export domain if that's relevant)

The DC/Cluster compat level is 4.7 and the vm was upgraded to it. 
"Original custom compatibility version 4.3 of imported VM xxx is not supported. Changing it to the lowest supported version: 4.7."

The disk is raw and sparse : 
<format>raw</format>
<sparse>true</sparse>

I initially put the VM's disks on an NFS storage domain, but I want to move the disks to an iSCSI one
However, after copying data for a while the task fails "User  has failed to move disk VM-TEMPLATE-COS7_Disk1 to domain iSCSI-STO-FR-301"

in engine.log : 
qemu-img: error while writing at byte xxx: No space left on device

2022-07-21 08:58:23,240+02 INFO  [org.ovirt.engine.core.vdsbroker.vdsbroker.GetHostJobsVDSCommand] (EE-ManagedScheduledExecutorService-engineScheduledThreadPool-Thread-48) [65fed1dc-e33b-471e-bc49-8b9662400e5f] FINISH, GetHostJobsVDSCommand, return: {0aa2d519-8130-4e2f-bc4f-892e5f7b5206=HostJobInfo:{id='0aa2d519-8130-4e2f-bc4f-892e5f7b5206', type='storage', description='copy_data', status='failed', progress='79', error='VDSError:{code='GeneralException', message='General Exception: ("Command ['/usr/bin/qemu-img', 'convert', '-p', '-t', 'none', '-T', 'none', '-f', 'raw', '-O', 'qcow2', '-o', 'compat=1.1', '/rhev/data-center/mnt/svc-int-prd-sto-fr-301.hostics.fr:_volume1_ovirt-int-2_data/1ce95c4a-2ec5-47b7-bd24-e540165c6718/images/d3c33cc7-f2c3-4613-84d0-d3c9fa3d5ebd/2c4a0041-b18b-408f-9c0d-971c19a552ea', '/rhev/data-center/mnt/blockSD/b5dc9c01-3749-4326-99c5-f84f683190bd/images/d3c33cc7-f2c3-4613-84d0-d3c9fa3d5ebd/2c4a0041-b18b-408f-9c0d-971c19a552ea'] failed with rc=1 out=b'' err=bytearray(b'qemu-img: error while writing at byte 13639873536: No space left on device\\n')",)'}'}}, log id: 73f77495

2022-07-21 08:58:23,241+02 INFO  [org.ovirt.engine.core.bll.StorageJobCallback] (EE-ManagedScheduledExecutorService-engineScheduledThreadPool-Thread-48) [65fed1dc-e33b-471e-bc49-8b9662400e5f] Command CopyData id: '521bdf57-8379-40ce-a682-af859fb0cad7': job '0aa2d519-8130-4e2f-bc4f-892e5f7b5206' execution was completed with VDSM job status 'failed'



I do want the conversion from raw/sparse to qcow2/sparse to happen, as I want to activate incremental backups.

I think that it may fail because the virtual size is bigger than the initial size, as I think someone as explained on this list earlier? Can anybody confirm? 
It seems to be a pretty common use case to support though? 
 
Guillaume Pavese
Ingénieur Système et Réseau
Interactiv-Group

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