QCOW2 to LVM-Thin Not Thin Provisioning


New Member
Oct 24, 2023
Hi all,
I'm attempting to move from QCOW2 to LVM-Thin however when moving the disks, the resultant RAW files are thick provisioned instead of thin? Is there a way to migrate from qcow2 whilst retaining the thin provisioning?

Thanks in advance
Here is the qcow2 of the vm, as can be seen its only 3.7G.
However, after migrating storage via the GUI to the LVM-Thin storage, it converts the qcow to a raw disk file which then occupies the full 64GB of space on the disk:
When I make a new drive and don't migrate from anything, then the thin provisioning works as expected and no additional space is used on the storage.
Trimming from the OS stated it had reduced the disk by 54GB however none of this has been reflected in the actual disk utilisation.
Any suggestions to trim this migrated drive down to its actual storage usage?
Last edited:
I'm unsure if you see the actual usage in the GUI. All my volumes are shown with their configured size, not their actual size on disk.
Check with lvs or lvdisplay if the shown value matches the value on disk.
Ok I have managed to fix the issue by first converting the qcow2 back to qcow2 as it they were originally made from RAW thick provisioned disks. I ran the following command:
qemu-img convert -p -f raw original.qcow2 -O qcow2 new-disk.qcow2

I then could migrate the storage from the GUI and the thin provisioning worked as expected.


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