April 2, 2026
File fights and Foxing nights
Foxing aspires to be an eBPF-powered replication engine for Linux filesystems
Speed demon or rsync remix? Foxing’s file mirroring sparks jokes and grilling
TLDR: A new Linux tool called Foxing promises near real-time one-way file mirroring with big speed claims, while its fxcp copy tool aims to outpace rsync. Commenters joked about the band name, asked how to run it over SSH, and pressed for answers on encryption, conflicts, and whether it’s a one-way replicator
The name alone sent the thread into chaos: “Foxing? Love that indie band,” cracked one commenter, before the devs clarified this isn’t emo—it’s a lightning-fast file mirroring tool. The project aims to mirror files on Linux almost in real time by watching changes inside the kernel using eBPF (tiny programs that run safely inside Linux) and replaying them to a target folder. Big claim: its smart copy tool, fxcp, posts eye-popping speed charts—“54x faster” on some big-file tests—while the always-on daemon, foxingd, promises sub-millisecond reaction time.
Cue the rsync faithful running the compare game. One user tried to translate the classic “rsync over SSH” into Foxing-speak, sketching a pipeline that streams a snapshot export over a secure shell into an import on the other side. That actually lines up with the new “streaming pipe” feature—so the vibes are hopeful, if a bit experimental. But the biggest chorus came from the cautious crowd: is the sync encrypted by default or do you roll your own with SSH/NFS? How are conflicts handled if two places change the same file? And is this a one-way replicator or a two-way sync (think Syncthing)?
Fans are hyped on the speed, features like seekable archives and chunk-level dedup, and the promise of a drop-in rsync/cp replacement. Skeptics are waving the “security and conflict policy” flag. The thread mood? Band jokes up front, hard questions in the back—and everyone wants to know if Foxing is a backup hero or just a very fast tease
Key Points
- •Foxing is an eBPF-powered replication engine for Linux filesystems (XFS, Btrfs, F2FS, Ext4) with event capture in the kernel and asynchronous replay for near real-time mirroring.
- •The project includes fxcp (smart copy tool without root/BPF) and foxingd (daemon) to deliver high-performance copying and continuous, event-driven mirroring.
- •Benchmarks show fxcp significantly outperforms rsync/cp in large, mixed, and sparse file tests (up to 54×, 10×, and 36× faster), with parity on many tiny files and mixed results over NFSv4.2.
- •fxcp auto-selects optimal transfer strategies (NFS compound RPC, reflink, sendfile, io_uring). foxingd reports single-file replication latency of 15–21 ms and is described as sub-millisecond.
- •v0.8.1 adds FXAR v2 with chunk-level dedup and seekable archives, streaming, parallel/pipelined operations, NFS session pooling, format auto-detection, tar export, pre-flight checks, and AVX2/AVX-512; earlier versions add JSON/progress, systemd notify, snapshot management, compression options, and filtering.