With the start of the New Year it now marks six years since the unexpected announcement of the Reiser5 file-system being developed as the continuation of the never-upstreamed Reiser4 file-system. But Reiser5 development never saw too much upstream interest and it’s now been several years without any updated patches for Reiser5 or Reiser4.
Every New Year’s Eve is a reminder of the Reiser5 announcement from 2019. Edward Shishkin who was a former Namesys developer and had been carrying along the Reiser4 maintenance since the conviction of Hans Reiser, explained of Reiser5 in its inaugural announcement as:
“I am happy to announce a brand new method of aggregation of block devices into logical volumes on a local machine. I believe, it is a qualitatively new level in file systems (and operating systems) development – local volumes with parallel scaling out. Reiser5 doesn’t implement its own block layer like ZFS etc. In our approach scaling out is performed by file system means, rather than by block layer means. The flow of IO-requests issued against each device is controlled by user. To add a device to a logical volume with parallel scaling out, you first need to format that device – this is the difference between parallel and non-parallel scaling at first glance.”
But six years later no public activity and in that time upstream file-systems like Btrfs, F2FS, and others continue tacking on new features. Out-of-tree options like Bcachefs and OpenZFS also have their loyal users for those advanced file-systems.
The v5-unstable on SourceForge hasn’t been touched now since April 2022 when updating the code for the Linux 5.16 kernel. The Reiser4 patches also haven’t been updated since that point either. The Reiser4 GitHub repository maintained by Edward Shishkin also hasn’t been touched since early 2022.
Edward pushed the Reiser file-system activities along further than anyone would have expected but given the lack of activity I wouldn’t expect any breakthroughs or sudden revivals in 2026.
