[abbbi]

proxmox is using LVM for direct attached raw volumes. LVM is just a logical volume manager for linux, which gives you more features than using old fashioned disk partitioning. I guess they chose this path for windows virtual machine migration because windows running on vmware before, does usually not have the required virtio drivers installed to support the qemu hypervisors virtio solution for disk bus virtualization out of the box. It would mean the hypervisor has to simulate IDE or SCSI bus which comes with great overhead perfomance wise (in the case of migration)

So an direct attached lvm volume is the best solution performance wise. In the vmware world this would be an direct attached raw device either from local disk or SAN.

For fresh install on proxmox its better to chose qcow as disk image format with virtio-scsi bus (comparable to vhdx, vmdk, qemus disk format) and add virtio drivers during windows setup.