Files
seaweedfs/seaweed-volume
Chris Lu cd5013f116 Re-check an EC shard map a failed read has disproved (#11023)
* Re-check an EC shard map a failed read has disproved

A read that fails against a cached location drops that shard from the map,
which leaves it one short of complete -- and a map one short is trusted for
seven more minutes. So a moment's trouble between volume servers cost
minutes in which every read of that shard skipped the direct fetch and paid
for a Reed-Solomon recovery instead, at DataShards times the memory and the
peer load.

Mark the map when a read disproves it, and re-check a marked map on the
same eleven-second footing as one that never had enough shards to begin
with. The mark clears on refresh, so it buys one prompt re-check rather
than a master lookup per read. The tiers move into a helper; they were
three overlapping conditions in one expression, and the reading of them
was not obvious.

Rust keeps the entry rather than dropping it -- a dead peer fails fast on
the next attempt, and it was the freshness window, not the entry, hiding a
shard that had moved.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Invalidate the location of an EC shard whose own read failed

Recovery fans out to the other shards, so the one whose direct read just
failed is the only location nothing ever invalidates: a shard that moved to
another server was reconstructed on every read until the map's own window
expired, up to thirty-seven minutes for a map still complete. Mark the map
there too. The entry stays -- a moved shard's old holder fails fast, and
the next refresh is seconds away.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Consume the stale mark before the lookup, not after

A read that fails while the master is answering has disproved the very map
that answer is about to install, and clearing the mark on the refresh's
return swallowed it. Clear it where it is acted on instead. A lookup that
then fails loses the mark, which costs nothing: the refresh time is only
advanced on success, so the next read looks up regardless.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Judge the shard map and consume its mark in one critical section

Reading the mark and clearing it were two separate acquisitions, so a mark
raised between them was cleared by a refresh that had not seen it. In Go
that gap was a few instructions; in Rust the mark was read when the read
first snapshotted the volume and cleared at the decision point, with the
local interval reads in between. Take both under one hold. Rust needs a
mutex rather than an atomic to do it, and no longer carries the mark
through the snapshot.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN

* Put the stale mark back when the lookup does not answer for it

Consuming the mark up front assumed the lookup would supersede it. A
lookup that fails, or comes back with fewer than DataShards holders,
supersedes nothing: the map is unchanged, its refresh time unadvanced, and
with the mark gone the map a read had disproved is trusted for its full
window again on the strength of a lookup that never landed. Put the mark
back on both branches.

Claude-Session: https://claude.ai/code/session_01SM5ARdPvFcnvGWNpBPgNRN
2026-08-28 15:43:05 -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 1.75+ (2021 edition).

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
--pprof false Enable pprof HTTP handlers

Set RUST_LOG=debug (or trace, info, warn) for log level control. Set SEAWEED_WRITE_QUEUE=1 to enable batched async write processing.

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.