Building a Soviet Nail Factory: how KPIs killed efficiency. A story that I often tell. It is now old enough to not upset my former colleagues. https://vincent.bernat.ch/en/blog/2026-kpi-goodhart
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Vincent Bernat
@vbernat@hachyderm.io
mastodon 4.7.3Network engineer at AS12322. Debian and free software developer. Like to work on projects with C, Python, or Go. He/him.
754 Followers
194 Following
37 Posts
Joined November 19, 2022
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Vince2_
I was about to write an article comparing semicolons in English with BGP confederations in networking: both of them are taught in class but shouldn't be used outside. Unfortunately, it seems the discourse around semicolons is more nuanced.
I had this article about contributing to RRDtool in draft for more than 10 years! I just published it "as is:" https://vincent.bernat.ch/en/blog/2013-contribute-rrdtool
The goal was to encourage people around me to contribute to open source. Unfortunately, the patch took a bit of time to be accepted (totally OK, but this undermined a bit the initial goal).
Just published Akvorado 2.4.1, your friendly IPFIX/NetFlow/sFlow collector: https://github.com/akvorado/akvorado/releases/tag/v2.4.1.
TIL: `export -f` in bash can export a function to a subshell
A most elegant TCP hole punching algorithm. Also a reminder that you can establish a TCP connection by initiating the connection on both sides at the same time (without a listening socket).
https://robertsdotpm.github.io/cryptography/tcp_hole_punching.html
Blogging with an LLM assistant: https://vincent.bernat.ch/en/blog/2026-blogging-llm (grammar, copyediting, translation). This specific post is *not* modified by an LLM.
From Milliseconds to 26 Nanoseconds: How a $20 eBay SFP Module Beat My Entire NTP Setup. It's a special SFP multicasting PTP frames to the network!
https://austinsnerdythings.com/2026/04/26/ptp-osa5401-26-nanoseconds-raspberry-pi/
A simplified version of htmx in 166 bytes. It's literally a one-liner to add to a web page!
New release of Akvorado. ClickHouse is now configured with some indexes that should help making queries faster. We are also switching to Quay.io for Docker images as it is available over IPv6, unlike GitHub registry (the images are available on both).
In Firefox, one tab for Outlook Web and one tab for Teams already eats 2.1GB of RAM. The next one is Zulip with only 150MB (which I think is OK).
OneUptime (a company trying to compete with DataDog with an open source product) is publishing AI slop on their blog at a very large scale.
https://github.com/OneUptime/blog/commit/30cd2384794c897d95aca77d173db44af51ca849
This (4-month old) bug in Claude Code is amusing. Even the best agentic LLM may trip on a file with tabs (and don't get it started with a non-breakable space). https://github.com/anthropics/claude-code/issues/11447
New release of Akvorado! Notably, there is performance enhancements for BMP, ability to import CSV for remote data sources, and a new heatmap visualization.
Amazing post on how to optimize measuring durations on Linux: https://www.hmpcabral.com/2026/04/26/the-fastest-linux-timestamps/
I have added the latest batch of releases of HAProxy to haproxy.debian.net. Since Ubuntu Resolute was released yesterday, I have also added HAProxy 3.2 and 3.3 packages.
https://haproxy.debian.net/#distribution=Ubuntu&release=resolute&version=3.2
David Crawshaw is building a new cloud. There are some interesting bits (local SSD with async replication, anycast out of the box).
Akvorado BMP provider was a challenge to scale properly. Thanks to the help of one contributor, some progress was made by introducing RIB sharding. Current tests seem to show this is fruitful with 60M routes handled without much sweat!
Twisted is still a thing! It's an event-based framework for network applications in Python. I used it a log 15 years ago!
Calculate “1/(40rods/hogshead) → L/100km” from your Zsh prompt. A small hack to turn "=" into a calculator (most of the work is done by Numbat or Qalc).
Math home work for senior year. Written with ChiWriter (a scientific word processor).
This tool looks well designed and polished: well-specified interface, minimalist, and a use case with NixOS read-only images. I keep it in the back of my mind.
Replying to
@zekjur@mas.to @leona@social.infinitespace.dev The wiki page explains it: https://nixos.wiki/wiki/Nix_channels Once Hydra has compiled release-25.11, the nixos-25.11 branch will be updated. This is a part that is a bit frustrating with NixOS: security updates can be delayed quite a bit. The status for each branch: https://status.nixos.org/
Rewrote my blog with Zine (not mine, Drew Devault). SuperMD and SuperHTML seem an interesting take for a better capable Markdown language.
RE: @rovarma@mastodon.gamedev.place
Well written and interesting article about a bug in Linux spinlock implementation. Worth the read!
Still on lldpd, I got three security issues that were found by some LLM. They are not directly actionable since you need to compromise the unprivileged process first. They are well described and each of them was correct.
https://github.com/lldpd/lldpd/issues/774
https://github.com/lldpd/lldpd/issues/773
https://github.com/lldpd/lldpd/issues/772
Looking at this issue in lldpd, I see two possible outcomes: 1. close the issue saying HP-UX is EOL end of 2025, 2. install HP-UX 11i with qemu and add support for it.
This MT7915 card seems supported by Linux and features two radios and could advertise 16 SSIDs. Anyone knows if they work well?
https://asiarf.com/product/wifi-6-11ax-dbdc-1800mbps-mini-pcie-module/
@pid_eins@mastodon.social Hey! Your blog returns connection refused for both v4 and v6 since about a week.
Replying to
@zekjur@mas.to The fix is still not present in NixOS 25.11. This is one of the main drawbacks of the Nix ecosystem. Hopefully, there is always a workaround (including just overlaying the patch from GitHub to nixpkgs, e.g. https://github.com/vincentbernat/homemanager-configuration/commit/b0bdf1009f914e9b78d9fc103783dfc196648868 )
Replying to
I have also started to document my LLM usage for blogging (see the small icon in the footer). I'll write more about it “later.”
I've asked IEEE the authorization to reproduce one diagram from IEEE 802.1Q (through https://standards.ieee.org/ipr/copyright-permissions-form/). Do they answer "fast"?