* storage: hold a below-minimum fsync batch open for stragglers When the durable-write queue drained, the worker flushed whatever it held, so low-concurrency fsync writes collapsed to one sync per request -- a seek plus a rotation on rotational media no matter the payload. Once the queue empties with the batch still below the configured minimum bytes and requests, the batch now stays open up to SyncBatchOption.Wait, armed once per batch so the added latency stays bounded. DiskLocation carries the option and defaults it; Store exposes a setter the server calls once at startup. * volume server: expose the fsync batch window as -fsync* flags -fsyncMinBatchBytes, -fsyncMinBatchRequests and -fsyncBatchWait carry the operator's batching floor into every disk's SyncBatchOption. -fsyncBatchWait=0 restores the previous flush-on-drain behavior. * server/mini: register the fsync batch window flags weed server and weed mini build their own VolumeServerOptions and left the three new fsync flag pointers nil, so startVolumeServer panicked dereferencing them at startup. * storage: bound the fsync batch window by Wait while the queue refills Once the straggler timer was armed, a steady trickle of queued writes kept taking the len(requests)>0 continue path, so the first write could wait past Wait until the size or count cap flushed the batch. Track the armed deadline and flush once it passes even with requests buffered. * storage: sync the straggler test on the worker taking the first write The fixed sleep let both writes queue together (passing under the old flush-on-drain behavior) or the straggler arrive after the window closed (flaky failure). Poll the drained queue instead so the second write can only land inside the armed window or a later batch. * volume server: default the fsync batch window when its options are unset weed server and weed mini build VolumeServerOptions without the fsync flag pointers, and outside embedders can too. Resolve the batch window from the defaults so startVolumeServer never dereferences nil options. * storage: drive the batch-window test through an injectable timer The window is armed by the worker now, so the straggler provably joins an open batch and expiry is fired by hand instead of racing a sleep. * seaweed-volume: accept -fsyncMinBatch/-fsyncBatchWait flags Same flags and defaults as weed volume so the Rust server's durable write batching can be tuned identically. * seaweed-volume: hold a below-minimum fsync batch open for stragglers Mirrors the Go worker's batchWait: once the queue drains under the minimum batch, the window stays open for stragglers and an expired window still bounds the batch while the queue refills. Paused-time coverage replaces any sleep-based assertion. * seaweed-volume: sync the straggler test on the armed batch window The test fired both writes together, so the straggler could already be queued when the worker drained — a regression that drops mid-window writes from the open batch would still pass. Wait until the worker arms the window before sending the last write (Go's test polls the drained channel for the same guarantee). Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com> * seaweed-volume: reject fsyncMinBatchBytes that does not fit usize --------- Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
SeaweedFS Volume Server (Rust)
A drop-in replacement for the SeaweedFS Go volume server, rewritten in Rust. It uses binary-compatible storage formats (.dat, .idx, .vif) and speaks the same HTTP and gRPC protocols, so it works with an unmodified Go master server.
Building
Requires Rust 1.91.1+ (2024 edition), matching rust-version in Cargo.toml.
The patch release matters: 1.91.0 does not build. The edition itself only needs
1.85; the higher floor comes from the dependency tree — chiefly the AWS SDK — so
it moves with those crates. CI builds on the latest stable.
cd seaweed-volume
cargo build --release
The binary is produced at target/release/seaweed-volume.
Running
Start a Go master server first, then point the Rust volume server at it:
# Minimal
seaweed-volume --port 8080 --master localhost:9333 --dir /data/vol1 --max 7
# Multiple data directories
seaweed-volume --port 8080 --master localhost:9333 \
--dir /mnt/ssd1,/mnt/ssd2 --max 100,100 --disk ssd
# With datacenter/rack topology
seaweed-volume --port 8080 --master localhost:9333 --dir /data/vol1 --max 7 \
--dataCenter dc1 --rack rack1
# With JWT authentication
seaweed-volume --port 8080 --master localhost:9333 --dir /data/vol1 --max 7 \
--securityFile /etc/seaweedfs/security.toml
# With TLS (configured in security.toml via [https.volume] and [grpc.volume] sections)
seaweed-volume --port 8080 --master localhost:9333 --dir /data/vol1 --max 7 \
--securityFile /etc/seaweedfs/security.toml
Common flags
| Flag | Default | Description |
|---|---|---|
--port |
8080 |
HTTP listen port |
--port.grpc |
port+10000 |
gRPC listen port |
--master |
localhost:9333 |
Comma-separated master server addresses |
--dir |
/tmp |
Comma-separated data directories |
--max |
8 |
Max volumes per directory (comma-separated) |
--ip |
auto-detect | Server IP / identifier |
--ip.bind |
same as --ip |
Bind address |
--dataCenter |
Datacenter name | |
--rack |
Rack name | |
--disk |
Disk type tag: hdd, ssd, or custom |
|
--index |
memory |
Needle map type: memory, leveldb, leveldbMedium, leveldbLarge |
--readMode |
proxy |
Non-local read mode: local, proxy, redirect |
--fileSizeLimitMB |
256 |
Max upload file size |
--minFreeSpace |
1 (percent) |
Min free disk space before marking volumes read-only |
--securityFile |
Path to security.toml for JWT keys and TLS certs |
|
--metricsPort |
0 (disabled) |
Prometheus metrics endpoint port |
--whiteList |
Comma-separated IPs with write permission | |
--preStopSeconds |
10 |
Graceful drain period before shutdown |
--compactionMBps |
0 (unlimited) |
Compaction I/O rate limit |
--compactionMaxParallelCommits |
0 (unlimited) |
Max concurrent vacuum commits |
--pprof |
false |
Enable pprof HTTP handlers |
Set RUST_LOG=debug (or trace, info, warn) for log level control.
Durable (fsync=true) uploads always go through per-volume batching workers
that share one .dat/.idx sync per batch, matching the Go volume server;
non-fsync writes take the synchronous path.
Features
- Binary compatible -- reads and writes the same
.dat/.idx/.viffiles as the Go server; seamless migration with no data conversion. - HTTP + gRPC -- full implementation of the volume server HTTP API and all gRPC RPCs including streaming operations (copy, tail, incremental copy, vacuum).
- Master heartbeat -- bidirectional streaming heartbeat with the Go master server; volume and EC shard registration, leader failover, graceful shutdown deregistration.
- JWT authentication -- signing key configuration via
security.tomlwith token source precedence (query > header > cookie), file_id claims validation, and separate read/write keys. - TLS -- HTTPS for the HTTP API and mTLS for gRPC, configured through
security.toml. - Erasure coding -- Reed-Solomon EC shard management: mount/unmount, read, rebuild, copy, delete, and shard-to-volume reconstruction.
- S3 remote storage --
FetchAndWriteNeedlereads from any S3-compatible backend (AWS, MinIO, Wasabi, Backblaze, etc.) and writes locally. SupportsVolumeTierMoveDatToRemote/FromRemotefor tiered storage. - Needle map backends -- in-memory HashMap, LevelDB (via
rusty-leveldb), or redb (pure Rust disk-backed) needle maps. - Image processing -- on-the-fly resize/crop, JPEG EXIF orientation auto-fix, WebP support.
- Streaming reads -- large files (>1MB) are streamed via
spawn_blockingto avoid blocking the async runtime. - Auto-compression -- compressible file types (text, JSON, CSS, JS, SVG, etc.) are gzip-compressed on upload.
- Prometheus metrics -- counters, histograms, and gauges exported at a dedicated metrics port; optional push gateway support.
- Graceful shutdown -- SIGINT/SIGTERM handling with configurable
preStopSecondsdrain period.
Testing
Rust unit tests
cd seaweed-volume
cargo test
Go integration tests
The Go test suite can target either the Go or Rust volume server via the VOLUME_SERVER_IMPL environment variable:
# Run all HTTP + gRPC integration tests against the Rust server
VOLUME_SERVER_IMPL=rust go test -v -count=1 -timeout 1200s \
./test/volume_server/grpc/... ./test/volume_server/http/...
# Run a single test
VOLUME_SERVER_IMPL=rust go test -v -count=1 -timeout 60s \
-run "TestName" ./test/volume_server/http/...
# Run S3 remote storage tests
VOLUME_SERVER_IMPL=rust go test -v -count=1 -timeout 180s \
-run "TestFetchAndWriteNeedle" ./test/volume_server/grpc/...
Load testing
A load test harness is available at test/volume_server/loadtest/. See that directory for usage instructions and scenarios.
Architecture
The server runs three listeners concurrently:
- HTTP (Axum 0.7) -- admin and public routers for file upload/download, status, and stats endpoints.
- gRPC (Tonic 0.12) -- all
VolumeServerRPCs from the SeaweedFS protobuf definition. - Metrics (optional) -- Prometheus scrape endpoint on a separate port.
Key source modules:
| Path | Description |
|---|---|
src/main.rs |
Entry point, server startup, signal handling |
src/config.rs |
CLI parsing and configuration resolution |
src/server/volume_server.rs |
HTTP router setup and middleware |
src/server/handlers.rs |
HTTP request handlers (read, write, delete, status) |
src/server/grpc_server.rs |
gRPC service implementation |
src/server/heartbeat.rs |
Master heartbeat loop |
src/storage/volume.rs |
Volume read/write/delete logic |
src/storage/needle.rs |
Needle (file entry) serialization |
src/storage/store.rs |
Multi-volume store management |
src/security.rs |
JWT validation and IP whitelist guard |
src/remote_storage/ |
S3 remote storage backend |
See DEV_PLAN.md for the full development history and feature checklist.