The Linux kernel regularly undergoes major developments driven by its community and its iconic creator, Linus Torvalds. The recent announcement of the removal of the Bcachefs code raises new questions about the integration and sustainability of file systems at the heart of open source. After being marked as “externally maintained” in version 6.17 of the kernel, Bcachefs was finally completely removed with the release of Linux 6.18. This removal is disruptive for users and developers who relied on this promising technology to improve data storage and management on Linux. This process highlights the complex challenges of software development in an environment as critical as the Linux operating system, balancing stability, innovation, and managing technical and human differences within a demanding community. Technical Background and Reasons for Removing Bcachefs from the Linux Kernel
Bcachefs, an open-source file system, aims to combine caching performance with advanced data management, establishing itself as a genuine alternative to systems such as Btrfs or XFS. Its initial goal was to offer greater resiliency, efficient snapshot management, and high performance thanks to an integrated cache. Incorporated into the Linux kernel starting with version 6.7, this file system quickly attracted the interest of many Linux enthusiasts and storage specialists. However, despite its potential, stability issues and sometimes chaotic development hampered its official adoption in the mainline kernel.
One of the major decisions made by
Linus Torvalds The decision taken with the release of Linux kernel 6.17 was to designate Bcachefs as “externally maintained.” This step meant that, although the code would still be present in the kernel, no new active contributions would be integrated directly by the core community. This stance reflected a desire to limit risks related to the system’s maturity while protecting users already engaged with Bcachefs. With the release of Linux 6.18, the situation changed: the Bcachefs code was completely removed from the kernel. Linus Torvalds justified this removal by pointing out the obsolete nature of the code in the kernel, now replaced by an external Distributed Kernel Module Support (DKMS) module. This move was intended to avoid confusion regarding kernel versions and ensure better overall system stability. In numbers, this translates into the removal of over 117,000 lines of code dedicated to Bcachefs from the kernel, a huge amount that underscores the significance of this decision. Bcachefs has been included in the Linux kernel since version 6.7
Moved to “externally maintained” status in Linux 6.17 Completely removed in Linux 6.18 to avoid version conflicts Moved to a DKMS module to maintain independent support
- Learn why the bcachefs file system was removed, the rationale for this decision, and recommended alternatives in the Linux world.
- Impact on the Linux community and open source software development
- The removal of Bcachefs highlights an undeniable reality in the Linux ecosystem: the need to balance innovation, rigor, and community cohesion. The file system is a central element of the kernel, and any change requires extreme vigilance to ensure the IT security and robustness of the entire system. This decision also reflects the tensions that can arise between core developers, external contributors, and maintainers, particularly when it comes to adhering to the rigorous software development cycle specific to the Linux kernel.
- This illustrates that, despite a very dynamic and passionate Linux community, managing projects in an open source model is not without challenges: it requires reconciling sometimes divergent technical visions and different practices in terms of code management and testing. Furthermore, the pressure on Linus Torvalds is high, as he must make drastic decisions to preserve the quality and stability of the kernel, even if this means removing poorly stabilized features. Importance of Respecting the Linux Kernel Development Lifecycle
Risks Associated with Integrating Immature Code into a Critical Database
Maintaining the Stability and IT Security of the Linux System
Mandatory Transition to Modularity via DKMS for Bcachefs
- https://www.youtube.com/watch?v=8E8Gb7Ikm2o
- Bcachefs as a DKMS Module: A Technical and Strategic Compromise
- The decision to switch Bcachefs to a DKMS (Dynamic Kernel Module Support) module provides a pragmatic solution for advanced users who wish to continue using this file system without directly relying on official kernel releases. A DKMS module allows for the compilation, installation, and maintenance of external drivers or file systems alongside the kernel, offering greater flexibility to system administrators and advanced users.
- For those wishing to install and use Bcachefs on popular distributions such as Ubuntu, Arch Linux, or NixOS, it is now necessary to use these non-kernel modules, which requires some adjustments, particularly during frequent kernel updates. This method, while less transparent than direct integration into the kernel, nevertheless prevents potentially unstable code from affecting overall computer security. DKMS ensures module compatibility with different kernel versions.
- Installation via dedicated packages or manual compilation depending on the distribution.
Facilitates development and testing outside the main kernel.
Avoids bottlenecks caused by late or unstable contributions.
For interested administrators, detailed tutorials are available explaining how to configure Bcachefs in DKMS mode, for example on Ubuntu or Arch and NixOS. This modularization supports an open source dynamic where critical system components can evolve independently of the kernel, while limiting the risk of instability within the Linux distribution.
- Find out why bcachefs was removed, its impact on users, and recommended alternatives. Analysis and advice for adapting to this change in the Linux file system ecosystem.
- Developer Tensions and Disagreements Around Bcachefs
- In 2025, discussions surrounding the integration of Bcachefs remain a striking example of the internal friction in Linux software development. On the one hand, Kent Overstreet, lead developer of Bcachefs, insisted on continuing to push fixes and adjustments until the final moments before the release of kernel 6.17, which led to tensions with Linus Torvalds and other maintainers. This refusal to strictly adhere to development cycles contributed to the final decision to retire Bcachefs in favor of external management.
- These events are reminiscent of previous cases encountered with other file systems such as XFS or Btrfs, where late changes sometimes complicated version validation. For the Linux community, learning to balance rapid integration with rigorous validation has become a central issue for maintaining kernel quality while still allowing for experimentation and innovation. Debate on Compliance with Release Candidate (RC) Rules
- Conflicts over Code Governance and Late Contributions
The Impact of Disagreements on Trust in File Systems Historical References to Previous File Systems Projects (XFS, Btrfs) Strategies to Limit Disruptions in the Linux Community To delve deeper into this issue, a comprehensive article analyzesthese disagreements between developers
https://www.youtube.com/watch?v=j1fNl-qjY1U
Consequences for Linux Users and System Administrators in 2025
The official removal of Bcachefs from the Linux kernel is forcing many users to adapt their infrastructures. Those who were using Bcachefs in production must now manage this file system as an external module, with all the constraints this entails in terms of maintenance and compatibility. For example, it has become imperative to monitor the evolution of the DKMS module to ensure proper integration with new kernel features.
- For system administrators, this situation requires:
- Increased vigilance regarding Linux kernel updates
- The need to integrate DKMS into their administration process
- More complex management of external module versions
- More advanced training to master module compilation and installation
Rigorous testing before any production deployment At the same time, other file systems continue to evolve and represent solid alternatives. Btrfs, in particular, which is constantly improving, and OpenZFS, maintain an important place in the Linux landscape, often favored for their maturity and proven stability. Technical comparisons, such as those published in specialist journals or on websites like Linux Encaja
Prospects for the evolution and robustness of the Linux kernel
Bcachefs’s departure invites us to reflect on the fundamental principles that govern Linux kernel development. This complex system requires a careful blend of rigor, innovation, and attention to the contribution lifecycle. While accommodating new features, it is essential that the kernel remains reliable and secure, particularly in a context where Linux is widely used in critical environments such as embedded computing, cloud servers, and IT security infrastructures.
This withdrawal illustrates the trend toward strengthening the kernel’s modularity by shifting experimental features to external modules. This approach ensures that emerging projects can continue to evolve freely while preserving the stability and cohesion of the system’s core. It represents a true technical and community compromise, marking a milestone in the history of open source software development around Linux. Maintaining essential quality and stability for the Linux kernel
- Encouraging modular and independent development
- Facilitating experimentation outside the mainline kernel
- Ensuring increased security for critical systems
- Ensuring the ever-more efficient future of multi-kernel architecture
- For a more technical dive into multi-kernel architecture and its relationship to file system management, consult
this dedicated resource .bcachefs retired: Find out why the bcachefs file system was removed, its consequences, and alternatives to consider for your Linux storage solutions.
