Files
seaweedfs/seaweed-volume
Chris LuandDevin d6a68468ad volume: keep a below-minimum fsync batch open for stragglers (#12016)
* 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>
2026-10-24 07:04:05 -07:00
..

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/.vif files 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.toml with 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 -- FetchAndWriteNeedle reads from any S3-compatible backend (AWS, MinIO, Wasabi, Backblaze, etc.) and writes locally. Supports VolumeTierMoveDatToRemote/FromRemote for 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_blocking to 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 preStopSeconds drain 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 VolumeServer RPCs 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.