OMV VM SMB Read / Write Speed Slow on VM Windows 11

[KorbiKorb]

Setup:​

I have set up an NVMe ZFS pool on my PVE and passed it through to an OMV (OpenMediaVault) VE using a SCSI drive. In the OMV-VM I mounted the drive via EXT4 and configured a SMB share.

The system runs on the following hardware:

• Proxmox Version: 8.3.0
• Host System: 16 x Intel(R) Xeon(R) Gold 6234 CPU @ 3.30GHz (2 Sockets), 192GB DDR4 EEC
• NVMe Storage: 2 x 1TB NVME
• ZFS Configuration: Mirror
• OMV Version: 7.7.1-3 (Sandworm)
• VM Network Adapter: virtio

Problem:
Additionally, I have two Windows 11 VMs with PCIe-passthrough GPUs to serve as powerful workstations for viewing large 3D models. These Windows VMs access the SMB share as a mapped network drive.

I tested the read/write speeds using a 5GB Windows ISO file, and the results are:

• Write speed over SMB: 500 MB/s
• Read speed over SMB: 200 MB/s

I'm expecting at least reaching the limit of the the 10Gbit from the virtio adapter.

Where is the bottleneck?

Thanks in advance!