frostvex

§ install

One line on Linux or macOS. Static single binary, ~8 MB, no runtime dependencies.

$ curl -fsSL https://frostvex.icu/install.sh | sh

Or grab a release from the install guide — pre-built binaries for x86_64 and aarch64. Windows users see below.

§ what it does

Frostvex synchronizes directories the way rsync tries to, but reworked for the kind of network most of us actually have — flaky home links, mobile hotspots, ssh sessions that reset every fifteen minutes. Three guarantees:

• If a transfer is interrupted, resume picks up at the byte boundary, not the file boundary.
• If two peers diverge, frostvex prefers the higher-version manifest and quarantines the loser instead of overwriting it.
• If a file made it across, the receiver can prove it bit-for-bit before you trust it. Reed-Solomon parity blocks survive a few corrupt sectors on the wire.

Lock-free architecture

Concurrent reads and writes against a single pool, without a global lock. Backed by a small CRDT for the manifest.

Bandwidth-efficient

Content-addressed delta transfer. On a typical photo library, the wire sees 0.5–2% of the file size after first sync.

Verified parity

BLAKE3 hashes on every chunk plus Reed-Solomon parity blocks. frostvex verify --strict catches silent corruption.

Peer-to-peer

No mandatory central server. Pull from a laptop, push to a NAS, sync across a mesh — all over QUIC.

§ a quick taste

Initialize a pool, point it at a remote, sync. That's the whole common path.

Inspect what's there:

The full quickstart walks through pull, peer discovery, and conflict resolution.

§ why another sync tool

I've used rsync for fifteen years and Syncthing for five. Both are good. But:

• rsync assumes a stable TCP connection. It doesn't have a manifest. If you cancel a transfer halfway, the receiver has half-files with no way to know which.
• Syncthing has a great UI and a great manifest, but it's eventually-consistent in a way that surprises you when an SSD fills up. And it pre-allocates, which on small VPSes is annoying.
• git-annex is the closest in spirit. But it carries a lot of perl-and-haskell weight, and asking it to handle 50 GB of holiday photos is unkind.

Frostvex is what I built when I got tired of papering over those edges with shell scripts. It's not trying to replace any of them — it's trying to fill a narrow slot: move a directory between two boxes I trust, on a link I don't trust, and tell me if anything went wrong.

§ not for you

Some honest non-goals — frostvex is probably wrong for you if:

• You need realtime sync between many edits per second. We batch on a 200 ms window. Use Syncthing or a CRDT-native editor.
• You want a web UI. There isn't one. Maybe in 0.5.
• You want encryption-at-rest on the server side. Use the operating system. Frostvex transports over TLS but does not transparently re-encrypt your files.
• You sync millions of tiny files. We've tested up to ~400k entries; past that, manifest hashing becomes a bottleneck.

§ recent posts

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