Basics of a Free Software Mirror (and how Debian does it)

Most Free Software projects don’t always have big-money backing, but they still need to distribute massive amounts of software binaries and data. That’s where download mirrors come in—they take the load off primary servers, improve availability, and speed up downloads, especially in different parts of the world.

In this talk, we’ll dive into the why, what, and how of setting up a Free Software mirror. You'll gain insight on what happens when you click download on any FS ecosystem sites and how your deb/rpm/appimage/exe/dmg are served from servers near you.

I’ve been running mirrors in India [1][2] and Germany [3] for a while now, and I’ll share my experiences [4] — the good, the bad, and the unexpected (hint - last year my mirror nodes pushed 1 PB+ of mirror traffic). All with nginx + rsync + cron and you can do it too (we still don't have a local KDE application data mirror [5]) :)

We’ll also how Debian ISO and packages are distributed [5]. It's a massive network consisting of commercial CDN (Fastly and AWS), universities, NRENs and individuals like you and me.

In closing, we'll also look at who's else is hosting mirrors in India [6].

[1] https://mirrors.in.sahilister.net/stats/
[2] https://2.mirrors.in.sahilister.net/stats/
[3] https://mirrors.de.sahilister.net/goaccess.html
[4] https://blog.sahilister.in/2024/06/first-iteration-of-my-free-software-mirror/
[5] https://blog.sahilister.in/2024/12/debian-mirrors-hierarchy/
[6] https://blog.sahilister.in/2024/10/free-software-mirrors-in-india/