The point of these next gen file systems aren’t raw performance, they are reliability, performance for specific cases, and reduced data usage. For example:
Copy on Write means it’s very performant to create snapshots
incremental backups are much quicker
checksumming means the filesystem directly and reliably detects data corruption
built-in support for raid means a simplified setup and integration of scrubbing features into the filesystem, which can then take advantage of checksumming etc.
deduplication can automatically recognize duplicated data and as such reduce data use
These are things that tend to reduce performance, not increase it. Which is why, when performance on these filesystems stays the same or even increases, that’s a major accomplishment.
Sorta related but these “next gen” FSs are pretty overrated on the performance benchmarks lots of groups like Phoronix do every kernel release.
BTRFS lags behind a ton compared to XFS, even though XFS was originally designed for large file throughput on servers.
Even EXT4 beats BcacheFS and BTRFS on several irl load benchmarks.
Only thing I’ve seen actually keep up is F2FS which iirc is the default on Android these days.
The point of these next gen file systems aren’t raw performance, they are reliability, performance for specific cases, and reduced data usage. For example:
Copy on Write means it’s very performant to create snapshots
incremental backups are much quicker
checksumming means the filesystem directly and reliably detects data corruption
built-in support for raid means a simplified setup and integration of scrubbing features into the filesystem, which can then take advantage of checksumming etc.
deduplication can automatically recognize duplicated data and as such reduce data use
These are things that tend to reduce performance, not increase it. Which is why, when performance on these filesystems stays the same or even increases, that’s a major accomplishment.
The point of COW filesystems isn’t performance. Comparing XFS and EXT4 to BTRFS/ZFS/Bcache is pointless.