Proxmox | Fix "e1000e Detected Hardware Unit Hang"

fix-eth-hang.md

Proxmox Virtual Environment 6.1-3 / Debian 10 (buster)
Kernel 5.3.10-1-pve
Ethernet controller: Intel Corporation Ethernet Connection (2) I218-V (rev 05)
Ethernet driver: e1000e 3.2.6-k
Ethernet firmware: 0.1-4

The solution I've found was to create a oneshot service which disables segmentation offloading.

sudo apt update && apt -y install ethtool

Create the file /usr/lib/systemd/system/fix-e1000e.service with the following content:

[Unit]
Description="Fix for ethernet hang errors"

[Service]
Type=oneshot
ExecStart=/usr/sbin/ethtool -K NETWORK_INTERFACE tso off gso off

[Install]
After=network-online.target
Wants=network-online.target

systemctl daemon-reload
systemctl enable fix-e1000e
systemctl start fix-e1000e

Looked good, but when trying it I get:

The unit files have no installation config (WantedBy=, RequiredBy=, Also=,
Alias= settings in the [Install] section, and DefaultInstance= for template
units). This means they are not meant to be enabled using systemctl.

Under [Install] add :
WantedBy=multi-user.target
to fix the error message report by frisbe
(source : https://unix.stackexchange.com/a/339537 )

It's much cleaner to do this in /etc/network/interfaces as follows:

iface eno1 inet manual
        post-up /usr/bin/logger -p debug -t ifup "Disabling segmentation offload for eno1" && /sbin/ethtool -K $IFACE tso off gso off gro off && /usr/bin/logger -p debug -t ifup "Disabled offload for eno1"

Change eno1 for your ethernet network name.