This library implements a FUSE filesystem that uses event sourcing to store data. This approach provides visibility into filesystem changes and allows restoring the filesystem to any previous point. In particular this library supports branching from specific points in the event history (see examples).

Example

use std::{fs, path::PathBuf};

use eventfs::{EventPageLimit, Filesystem, FilesystemConfiguration};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Create the local mount point used by FUSE.
    let mount_point = PathBuf::from("eventfs.mount");

    fs::create_dir_all(&mount_point)?;

    // Open the filesystem and mount it in the background.
    let configuration = FilesystemConfiguration::new("eventfs.db", mount_point.clone())?;

    let filesystem = Filesystem::open(configuration)?;

    let _ = filesystem.spawn_mount()?;

    // Write a file through the mounted filesystem.
    fs::write(mount_point.join("hello.txt"), "Hello from eventfs!")?;

    // Print the events created by filesystem changes.
    for event in filesystem.events(EventPageLimit::new(10)?) {
        println!("{:?}", event?);
    }

    Ok(())
}

FUSE operation support

• lookup
• getattr
• setattr
• readlink
• mknod
• mkdir
• unlink
• rmdir
• symlink
• rename
• link
• open
• read
• write
• flush
• release
• fsync
• opendir
• readdir
• releasedir
• fsyncdir
• statfs
• setxattr
• getxattr
• listxattr
• removexattr
• access
• create
• readdirplus
• getlk
• setlk
• bmap
• ioctl
• poll
• fallocate
• lseek
• copy_file_range

Benchmarks

• Measured with ./dev.sh bench on July 7, 2026.
• Apple M4 Pro host, macOS 26.2 25C56.
• Apple container Linux VM, Linux 6.18.15 aarch64.
• 14 CPUs and 49.3 GB RAM exposed to the container.
• FUSE 3.14.0.

Operation	eventfs mean	host mean	eventfs / host
lookup	218.10 ns	215.93 ns	1.0x
getattr	126.87 ns	134.23 ns	0.9x
setattr_metadata	35.335 µs	281.02 ns	125.7x
setattr_size	69.746 µs	460.16 ns	151.6x
access	207.64 ns	195.96 ns	1.1x
statfs	28.540 µs	272.90 ns	104.6x
mknod	83.455 µs	827.73 ns	100.8x
mkdir	86.459 µs	53.654 µs	1.6x
create	96.319 µs	1.0122 µs	95.2x
unlink	71.465 µs	1.0185 µs	70.2x
rmdir	73.510 µs	1.3399 µs	54.9x
rename	96.569 µs	984.11 ns	98.1x
rename_noreplace	97.273 µs	1.0241 µs	95.0x
link	96.447 µs	665.70 ns	144.9x
symlink	94.376 µs	998.58 ns	94.5x
readlink	25.142 µs	248.45 ns	101.2x
open	25.858 µs	254.93 ns	101.4x
read	28.343 µs	201.09 ns	140.9x
write	55.232 µs	235.94 ns	234.1x
flush	108.30 ns	107.50 ns	1.0x
release	2.8680 µs	153.36 ns	18.7x
fsync	54.416 µs	26.272 µs	2.1x
opendir	22.105 µs	381.32 ns	58.0x
readdir	51.691 µs	535.39 ns	96.5x
readdirplus	111.06 µs	4.3872 µs	25.3x
fsyncdir	51.064 µs	26.538 µs	1.9x
releasedir	2.6518 µs	156.46 ns	16.9x
setxattr	55.985 µs	370.63 ns	151.1x
getxattr	23.552 µs	292.10 ns	80.6x
listxattr	23.789 µs	261.39 ns	91.0x
removexattr	56.521 µs	351.28 ns	160.9x