Fixing Proxmox Realtek NIC Freezes During Restores

- Restore starts normally (~80 to 90 MB/s)

- After 4 to 5 minutes, network traffic drops to 0

- Task hangs indefinitely

- Backups (TX) work fine

- The issue only occurs during heavy inbound traffic (RX)

Limiting bandwidth (10 to 40 MB/s), disabling offloads, and lowering the MTU all fail to prevent the hang.

- Mini-PC with Intel i5-12450H

- Realtek RTL8111/8168/8411 (rev 15)

- Default r8169 driver

- RX ring buffer limited to 256 entries

- UniFi network (IPS/IDS off, jumbo frames off)

The restore process eventually fails with:

backup write data failed:write_data upload error:pipelined request failed: timed out

Realtek PCIe NICs in many mini-PCs struggle with sustained inbound traffic. Restores from Proxmox Backup Server generate continuous RX load, which exposes these weaknesses:

- Tiny RX buffers

- Unstable r8169 driver behavior

- Poor offloading consistency

- Thermal and PCIe limitations

The bottleneck is the hardware. PBS and the network configuration are not the cause.

Installing r8168-dkms (and blacklisting r8169) sometimes improves stability, but results vary. It does not raise the hardware RX buffer limits, so sustained load may still trigger hangs.

It is worth testing, but there is no guarantee it will help.

Option 1: USB 3.0 NIC

- AX88179-based adapter

- Better RX handling

- Little downtime to set up

- Good for mini-PC hosts

Option 2: Intel NIC

- i210, i225 or i350 recommended

- Larger RX buffers

- Production-grade stability

- Best long-term solution

Backups generate outbound traffic (TX), while restores generate sustained inbound traffic (RX). The Realtek NIC fails under RX saturation because of limited buffering and driver instability.

Is this a Proxmox Backup Server bug?

No. The issue appears under heavy inbound traffic and comes from the hardware.

Can bandwidth limiting solve it?

No. Even restores at low bandwidth still hang after several minutes.

Is this common on mini-PCs?

Yes. Many mini-PCs use Realtek NICs with small RX buffers, which makes them unreliable for long restore workloads.

What is the safest production fix?

Replace the Realtek NIC with an Intel-based adapter or use a stable USB 3.0 Ethernet adapter.