A reminder that Reiser4 exists and is still getting updated. Fast, stable, and most of all: atomic (only one core though).

You'll need to patch your kernel[0] and install the mkfs.resier* util[1]. Take a look at this Gentoo-forums tweaks post[2] for troubleshooting and performance tweaks. If you find reiser is lagging, your filesystem was likely built incorrectly and you'll need to run a simple

     fsck.reiser4 -y --fix --build-fs --build-sb

on your partition and it should be fixed. I only made the switch recently because Ext4 doesn't have intelligent inode allocation and drops the ball at 1mil files.

[0]https://sourceforge.net/projects/reiser4/files/reiser4-for-l...

[1]https://sourceforge.net/projects/reiser4/files/reiser4-utils...

[2]https://forums.gentoo.org/viewtopic-t-707465-postdays-0-post...