Released last week was [1]Bcachefs 1.38.6 with a host of performance improvements to this out-of-tree, copy-on-write file-system. Given all the performance improvements and this being the first release since Kent Overstreet dropped the "experimental" flag on the file-system, I decided to fire up some benchmarks looking at how the Bcachefs file-system performance has changed with this new version.

[2]

[3]Bcachefs 1.38.6 drops the experimental tag for the file-system, improves device/data management, optimizes the erasure coding, and has a wide variety of other performance optimizations over prior releases. All the details on the new Bcachefs 1.38.6 changes can be found via Kent Overstreet's [4]Patreon for the project.

[5]

Bcachefs continues to be developed outside of the Linux kernel source tree but [6]DKMS packages are available for easy deployment on modern Linux distributions. For the purposes of today's testing, I compared Bcachefs 1.38.6 to the former Bcachefs 1.38.5 release on the same system for seeing how the performance has evolved.

[7]

Once the Linux 7.2 merge window has passed and Bcachefs also supporting Linux 7.2, I will be around with some fresh file-system comparison benchmarks for Bcachefs against the likes of Btrfs, EXT4, F2FS, and XFS. A lot of improvements continue to flow throughout the open-source file-system ecosystem.

For today's round of testing an AMD Ryzen Threadripper 9980X workstation running Ubuntu 25.10 was used with the official Bcachefs 1.38.5 and 1.38.6 packages from the upstream Bcachefs repository. Both times Bcachefs was freshly formatted and mounted using the default mount options. The Samsung 9100 PRO 1TB NVMe SSD was used for all of the Bcachefs benchmarks. No other changes were made to the software or hardware state besides this Bcachefs version comparison.



[1] https://www.phoronix.com/news/Bcachefs-Tools-1.38.6

[2] https://www.phoronix.com/image-viewer.php?id=bcachefs-1386&image=bcachefs_1386_1_lrg

[3] https://www.phoronix.com/search/bcachefs

[4] https://www.patreon.com/bcachefs/posts/1-38-6-release-161366372?

[5] https://www.phoronix.com/image-viewer.php?id=bcachefs-1386&image=bcachefs_1386_2_lrg

[6] https://www.phoronix.com/news/Bcachefs-Debian-Ubuntu-DKMS

[7] https://www.phoronix.com/image-viewer.php?id=bcachefs-1386&image=bcachefs_1386_3_lrg