TPM disk format

[Digambar Borse]

Hi,
By default Proxmox adds TPM disk in raw format, but we wanted to use qcow2 disk for TPM disk . so I set a qcow2 disk to VM by following command.

qm set 107 -tpmstate0 "storage1-ext4:107/vm-107-disk-4.qcow2,size=4M,version=v2.0"

After setting I again checked disk format

qemu-img info /mnt/pve/storage1-ext4/images/107/vm-107-disk-4.qcow2

It was show disk format as qcow2.
But on next day I observed that snapshot option was disabled , and when I checked disk format again then I observed that disk format was shown as raw format.
Why the TPM disk format is changed automatically ?

Any suggestion/opinion.

Thanks
-Digambar

 

[Daniel-Doggy]

This is because qcow2 is not supported for vTPM
vTPM only supports raw.

 

[Digambar Borse]

Thanks Daniel,
If its allowed to set qcow2disk as TPM disk then why its format is changed later. Is there any way to use qcow2 disk for TPM disk?

 

[Daniel-Doggy]

Thanks Daniel,
If its allowed to set qcow2disk as TPM disk then why its format is changed later. Is there any way to use qcow2 disk for TPM disk?

Its not really allowed.
The command you entered allows you to set broken configuration.
Proxmox VE was just smart enough to correct it by itself.

 

[Daniel-Doggy]

https://github.com/stefanberger/swtpm/issues/986
Not directly Proxmox VE but same qemu. So it also applies to proxmox VE.

 

[fiona]

See also: https://bugzilla.proxmox.com/show_bug.cgi?id=4693