ObsidianOS

Overview

ObsidianOS is a free, open-source GNU/Linux distribution based on Arch Linux, with A/B partitioning as its core innovation, providing a reliable rollback mechanism during system updates (similar to Android and ChromeOS). It emphasizes stability, atomic updates, and user-mode overlays. Maintained by community developers and hosted on GitHub and SourceForge, it supports the x86_64 architecture and uses systemd and the EXT4 file system. ObsidianOS employs a rolling release model (similar to Arch), but avoids disruptive updates through A/B partitioning, and offers multiple editions (such as Base Edition and COSMIC Edition).

History and Development

• Origins:
  • Around 2024: The ObsidianOS project was launched by independent developers as a fork of Arch Linux, aiming to address the problem of traditional Linux updates easily breaking the system by introducing A/B partitioning.
• Early Development:
  • 2024: Initial version released, using a TUI installer and supporting basic A/B rollback.
• Key Milestones:
  • Early 2025: Introduced a graphical installer and multiple editions (Base, COSMIC).
  • August 2025: Added user-mode overlays (Rust implementation, no kernel modules required) and overlaid packages.
  • November 2025: Latest update, optimizing the obsidianctl GUI, plugin system, and COSMIC desktop edition.
• Current Status:
  • The project is active on GitHub (28 repositories), with a small but innovative community, and is rising in the DistroWatch rankings. Developers emphasize that it's "not just a re-themed Arch," but a rethinking of the update mechanism.

Main Features

1. A/B Partitioning Layout:
   • Dual root file systems (A/B), updates are written to the inactive partition, switching occurs upon reboot, and rollback only requires a reboot.
2. User-mode Overlays:
   • Implemented in Rust, intercepts libc calls to create layered file systems, without requiring btrfs/ZFS.
3. Installation and Management:
   • Graphical/TUI installer (modified ArchISO), supports the COSMIC desktop environment.
   • obsidianctl: Qt6 GUI control center for managing updates/rollbacks.
4. Desktop Environment:
   • Base Edition: Minimal;
   • COSMIC Edition: Rust-based COSMIC desktop.
5. Package Management:
   • pacman (Arch standard), rolling release.
6. Hardware Compatibility:
   • x86_64 UEFI-only, EXT4/f2fs support.
   • Minimum requirements: 2 GB RAM, 20 GB disk space.
7. Security and Privacy:
   • Arch security model + A/B rollback for enhanced reliability.
8. Development Support:
   • Full Arch toolchain (gcc, rust, go, etc.).

Advantages and Limitations

Advantages:

• Atomic Updates: A/B partitioning + rollback, superior to standard Arch in terms of risk of breakage.
• Innovation: User mode overlays and overlaid packages, experimental but powerful.
• Arch Ecosystem: Full inheritance of rolling release, pacman, and AUR.
• Lightweight: Base Edition is minimal, suitable for older hardware.
• Community Feedback: Reddit calls it "a rare truly innovative Arch derivative."

Limitations:

• Young Project: Small team, long-term maintenance uncertain.
• Highly Experimental: Overlays/plugins are still in early stages, potentially buggy.
• Not Suitable for Beginners: Arch base + A/B configuration requires experience.
• Community Size: Smaller than EndeavourOS/Manjaro.
• Comparison with other distributions:
  • Arch Linux: Pure rolling release, no A/B.
  • EndeavourOS: User-friendly Arch installation.
  • ChromeOS: Similar A/B, but closed source.
  • Fedora Silverblue: Atomic updates (ostree).
  • Vanilla OS: Similar immutable root.

Summary

ObsidianOS is an innovative Arch Linux derivative, centered around A/B partitioning and user mode overlays, providing atomic updates and reliable rollback. The latest update was in November 2025. It is suitable for users who want Arch's rolling release but are tired of disruptive upgrades, and with the COSMIC desktop and obsidianctl GUI, it is suitable for desktop development/creative work. Compared to Arch (pure rolling release), EndeavourOS (user-friendly), Fedora Silverblue (atomic ostree), and ChromeOS (similar A/B system), ObsidianOS stands out for its experimental nature and rollback mechanism, but the project is young and has a small community.