NixOS on Wael Nasreddine

Why I Use NixOS

Sun, 24 Mar 2019 00:00:00 +0000

This post highlights my reasoning behind switching to NixOS.

This was originally posted as a Reddit comment.

Linux/Unix History Link to heading

Please head over to read all about my Linux/Unix History. In a Gist: I have about 20 years experience in using and managing Linux and Unix machines ranging from various Linux distributions, as well as *BSD and by extension Darwin (a.k.a Mac).

Why did I switch to NixOS? Link to heading

Last year -- 2018 -- I was still working as a co-founder of a small Ad-related startup. I used to have crazy long days (averaging about 12-16 hours), and I used to do about ten different things (in parallel). The reliability of my machine to say the least is of utmost importance as my day (and thus my productivity) depends on it. One day early May of last year, I wanted to install a new Vim plugin (can't remember the exact plugin) and I inadvertently ran :PlugUpdate which updated all of my Vim plugins to the latest version and this has broken my entire Go setup. Not only I could no longer get auto-completion as I was typing, but I was also greeted with a multi-line error every time I open a Go file, attempted to edit something or save it. I had to disable most of my plugins just to get by. By the end of that day, I was very much late on my tasks and extremely frustrated, I decided to take the weekend off and look for a solution!

Announcing the new Golang infrastructure: buildGoModule

Sun, 17 Mar 2019 00:00:00 +0000

Important

This guide was written on March 17^th 2019 and thus is out of date! Please refer to Go section in the nixpkgs manual for a more up-to-date instructions!

I recently introduced a new function in Nixpkgs named buildGoModule. The new function allows you to package Go application (or modules) with ease, provided the modules have added support for Go modules upstream.

Go, starting at version 1.11, has shipped with an internal solution for vendoring dependencies named: Go Modules. This feature provides a pseudo-lockfile-based implementation for vendoring dependencies, with one guarentee: Reproducible build. This means that all the dependencies are guarenteed to be the same.

CDC: Why Decompression is Worth the Complexity

Mon, 01 Jan 0001 00:00:00 +0000

When I started building ncps, a Nix cache protocol server, the fundamental question was: should we chunk compressed NARs or decompress first?

Decompressing before chunking adds CPU cost and complexity. Compressing individual chunks adds storage overhead. It seemed wasteful. The naive approach — chunk the compressed NAR directly — is simpler and avoids the extra round-trip through decompression and recompression.

But I had data. Over a year of real-world use, I'd accumulated 60,910 NAR files across multiple nixpkgs revisions and platforms. Before committing to the complex path, I wanted empirical evidence.

Content-Defined Chunking (CDC) Results for NAR Storage

Mon, 01 Jan 0001 00:00:00 +0000

I’ve been benchmarking Content-Defined Chunking (CDC) to optimize storage for our NAR files. The goal was to maximize deduplication by decompressing the source NARs before chunking, then re-compressing the unique chunks for final storage.

The Pipeline: Compressed NAR → Decompress → CDC Chunking → Re-compress Chunks → Store

Summary Statistics Link to heading

Metric	Value
Total Files (NARs)	60,784
Original Compressed Size	161.06 GB
Post-Deduplication Size	125.46 GB
Net Space Saved	35.60 GB (22.1%)
Unique Chunks Stored	3,934,658
Deduplication Hit Rate	47.72%

Database Insights Link to heading

The following queries highlight the storage efficiency and the chunk distribution across the dataset.

Install ArchLinux from within NixOS

Mon, 01 Jan 0001 00:00:00 +0000

Introduction Link to heading

Note

This is more of a journal entry (of a self-challenge) than a guide. I call my device Hercules and my ZFS pool is named olympus. If you decide to follow this guide, make sure to reference the sources at the bottom.

Caution

Backup your ZFS pool. I am not responsible if you end up losing your data. Please proceed with caution.

Install Debian or Ubuntu from within NixOS

Mon, 01 Jan 0001 00:00:00 +0000

Introduction Link to heading

Note

Caution

Backup your ZFS pool. I am not responsible if you end up losing your data. Please proceed with caution.

NixOS - ZFS - No space left on device

Mon, 01 Jan 0001 00:00:00 +0000

Problem Link to heading

My system ran out of space, and I am unable to run sudo nix-collect-garbage -d.

❯ sudo nix-collect-garbage -d
removing old generations of profile /nix/var/nix/profiles/per-user/root/channels
error: opening lock file '/nix/var/nix/profiles/per-user/root/channels.lock': No space left on device

Solution Link to heading

Remove your ~/.cache/nix and you should be able to collect the garbage and untangle your system.