Reiser5 File-System In Development - Adds Local Volumes With Parallel Scaling Out
Edward Shishkin has continued maintaining the Reiser4 file-system over the decade for new kernel releases even with no aim for mainline inclusion. Reiser4 has continued to be maintained while the likes of Btrfs, F2FS, EXT4, XFS, and ZFS On Linux among others have continued advancing... But Shishkin has quietly been working on advancing the Reiser file-system design and today announced format 5, a.k.a. Reiser5.
Reiser5 is described by the former Namesys developer 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."
Reiser5 should deliver better performance and other benefits over Reiser4. The Reiser5 announcement comes as a surprise and just learned of it via automatic notifications of my Reiser4 monitoring via SourceForge.
The Reiser5 whitepaper explaining its design and other technical details in fine detail can be found via the reiserfs-devel mailing list. I am still pouring through the paper myself and it's a lengthy but very interesting technical read. I'll be working on some Reiser5 benchmarks shortly.
The initial development code of Reiser5 for patching against the upstream Linux 5.4.6 kernel can be found via SourceForge. There is also Reiser4Progs 2.0.0 as the user-space utilities now updated for handling Reiser Format 5.
It will be interesting to see if Reiser5 attracts the interest of any new parties and could potentially make its way upstream... Granted, many would likely want to see Reiser5 renamed due to the connection to Reiser file-system's founder and convicted murderer, Hans Reiser. Hans is still serving his fifteen year sentence until 2023 for murdering his wife but can see parole eligibility as soon as next month (January 2020).
Among the items still on the Reiser5 TODO list are upgrading FSCK to support logical volumes, burst buffers, asymmetric LV with more than one meta-data brick per volume, symmetric logical volumes, 3D snapshots of LVs, and global logical volumes.