• BIOS Firwmare
• Device Page

I should have taken more notes when this came up. I don't think this is actually related because it was fixed in kernel 4.15 and I'm running 5.4.

https://forum.proxmox.com/threads/e1000e-0000-00-1f-6-enp0s31f6-detected-hardware-unit-hang.50640/

https://docs.hetzner.com/de/robot/dedicated-server/troubleshooting/performance-intel-i218-nic/

I did run this:

ethtool -K enp0s31f6 tx off rx off

2021-05-05: After 40 days of uptime, I think I can conclude that this did at least work around the issue.

00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection I219-LM (rev 21)
6c:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller (rev 0c)

• update-grub find non-existent devices

  root@gw:~# lsblk
  NAME                MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
  sda                   8:0    0 745.2G  0 disk 
  |-sda1                8:1    0   512M  0 part /boot/efi
  `-sda2                8:2    0 744.7G  0 part 
    |-vgubuntu-root   253:0    0 743.7G  0 lvm  /
    `-vgubuntu-swap_1 253:1    0   976M  0 lvm  [SWAP]
  
  root@gw:~# grep -Fn "global_filter" /etc/lvm/lvm.conf
  158:	# Configuration option devices/global_filter.
  162:	# Use global_filter to hide devices from these LVM system components.
  164:	# global_filter are not opened by LVM.
  166:	# global_filter = [ "a|.*|" ]
  167:    global_filter = [ "r|/dev/sdb|" ]
  
  
  root@gw:~# update-grub
  Sourcing file `/etc/default/grub'
  Sourcing file `/etc/default/grub.d/init-select.cfg'
  Generating grub configuration file ...
  Found linux image: /boot/vmlinuz-5.4.0-66-generic
  Found initrd image: /boot/initrd.img-5.4.0-66-generic
  Found linux image: /boot/vmlinuz-5.4.0-65-generic
  Found initrd image: /boot/initrd.img-5.4.0-65-generic
  Found linux image: /boot/vmlinuz-5.4.0-62-generic
  Found initrd image: /boot/initrd.img-5.4.0-62-generic
  Adding boot menu entry for UEFI Firmware Settings
  done