@LnxBil: This was because I have a 480Gb and another 960Gb SSD's.
The gaol was to passthrough the 480 for my home server, but this week I reinstalled my PVE and migrated from QCOW2 on LVM volume to LVM-Thin. The 480Gb is now dedicated to VM's OS, and the 960 to VM Data's.
@Toni G: Yes, with HDD passthrough you can backup using web interface, and restore. But restore is only on PVE "conventional" storage.