e1000e: Detected Hardware Unit Hang
Are you, as I, suffering from Detected Hardware Unit Hang in the kernel log from an e1000e network card? How do you notice it. A transfer goes to zero bytes for around 10 seconds, then restarts, then goes to zero, then restarts and so on…
Portable Hardware Locality (hwloc)
From the website: The Portable Hardware Locality (hwloc) software package provides a portable abstraction (across OS, versions, architectures, …) of the hierarchical topology of modern architectures, including NUMA memory nodes, sockets, shared caches, cores and simultaneous multithreading. It also gathers various system attributes such as cache and memory information as well as the locality of I/O devices such as network interfaces, InfiniBand HCAs or GPUs.
List CPU vulnerabilities
Oneliner to list your CPU vulnerabilities and mitigations. Read more about the different vulnerabilities and mitigations at Hardware vulnerabilities.
Bootstrap Debian VM with virt-install
Installing a small Debian VM from scratch with only one partition. Makes later resizing easier. This was done on Fedora 32.
Preparations Install software libvirt is already installed on Fedora 32. It’s used in Gnome Boxes. We will not use that for this. We’ll do it the old fashioned way with virt-install.
Libvirt and Vagrant
Libvirt is the default toolkit to manage virtualization platforms on Linux. Libvirt and qemu is a great combination with Vagrant. It’s the default combination on most Linux systems, also on my favorite - Fedora.
This combination allows for some awesome features and some restrictions. One of the restrictions is that Ubuntu isn’t available as a box, but Debian is.
Vagrant with Ubuntu Focal (20.04)
Vagrant is a great way to script development environments for system administrators. It works with full virtualization and is closer to the real hardware than container systems.
There is a bug in the latest version of Ubuntu (Vagrant Box) that makes it hang during boot. It even hangs the VirtualBox and makes the GUI misbehave.
Design an online ransomware safe backup with restic
The only way to be safe for ransomware, except for keeping a offline backup, is to have a immutable online backup.
restic is a deduplication backup sofware, designed for ease of use and security. Rclone is a versatile program for syncing data between a huge variety of protocols and cloud providers.
SSH with YubiKey NEO on Fedora made easy
Your private SSH key is the key for the kingdom. This means always having a password on the key. With YubiKey, you can keep your secret key outside your machine too.
Excerpt from Wikipedia: The YubiKey allows users to sign, encrypt and decrypt messages without exposing the private keys to the outside world.
Distributed syncing with Syncthing
I’ve tried to ditch Dropbox for a long time. But the need for synchronizing folders between my computers have held me back. Syncthing solves this for me. It’s decentralized syncrhonization between all my units, including my phone, without the need to go through a 3rd party server.
Excerpt from Syncthings homepage: Syncthing replaces proprietary sync and cloud services with something open, trustworthy and decentralized.
Compressed RAM based block devices
From zram documentation: The zram module creates RAM based block devices named /dev/zram(= 0, 1, …). Pages written to these disks are compressed and stored in memory itself. These disks allow very fast I/O and compression provides good amounts of memory savings. Some of the usecases include /tmp storage, use as swap disks, various caches under /var and maybe many more :)