Files
seaweedfs/seaweed-volume
Chris Lu 31fb46f693 volume: rebuild a missing .idx from the .dat (#11115)
* volume: rebuild a missing .idx from the .dat

Pointing -dir.idx at a directory that holds no index aborted the whole
volume server: checkIdxFile found no .idx and load() called glog.Fatalf.
Every row of the index is derivable from the .dat, so walk it in append
order and write the index back, which reproduces byte for byte what the
server's own writes had left in the old directory.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* volume: keep the index co-located with the data in the Rust server

Go's load() drops back to the data directory when an .idx already sits
beside the .dat, so naming a --dir.idx does not strand a pre-existing
index. Rust had no such adjustment: it opened the new directory with
create, and the volume came up on an empty index with every needle
invisible.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* volume: rebuild a missing .idx from the .dat in the Rust server

Mirrors the Go side. Rust did not abort on a missing index the way
checkIdxFile did; it opened the new directory with create and mounted the
volume on an empty index, so every needle read as missing while the .dat
still held the data. Walk the .dat in append order and write the index
back, byte for byte what the server's own writes had left behind.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* volume: stop the idx rebuild at a zero-padded .dat tail

An all-zero needle header is unwritten space, not a record. Go's .dat walk
keeps reading past it and would index a truncated data file's tail as
millions of needle 0 rows; the Rust walk already stops there. Stop the Go
rebuild at the same place.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* volume: create the -dir.idx directory when it does not exist

Rust's DiskLocation creates the index directory as it takes it; Go only
resolved the path, so naming a directory that does not exist yet left every
volume unable to open or rebuild its index and took the server down.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* volume: stop the idx rebuild at a torn .dat record

A crash between writing a needle's header and its body leaves a record
whose declared size runs past the end of .dat. Indexing it puts a row in
the .idx that points at bytes that do not exist, which fails every read of
that needle and trips the past-EOF check on the next load. Stop at the
first record that does not fit, in both servers.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* volume: stop the idx rebuild at a negative-size header

A corrupt header whose size field is negative makes the .dat walk advance
backwards: NeedleBodyLength adds the negative size, so the next offset is
lower than the current one. The Go walk then reads at a negative offset and
the rebuild fails, which puts the volume server right back to exiting at
startup; the Rust walk seeks past EOF and truncates the index instead.
A negative size is never a record, so stop there.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* volume: skip a volume whose index cannot be rebuilt, do not exit

glog.Fatalf calls os.Exit(255), so a rebuild that could not write -- a full
or read-only index directory -- put the server right back to dying at
startup for one bad volume. Return the error instead: loadExistingVolume
logs it and skips that volume, which is what the remote-volume branch just
above already does and what the Rust loader has always done.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* volume: create the index directory from the rebuild too

The rebuild is the first thing to write into a fresh -dir.idx, and it runs
before the loaders that create the directory on their way to opening .idx.
Create it in both rebuilds so the ordering does not matter.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ

* ci: let codespell past the sme variable in the mount tests

weedfs_stream_mutate_error_test.go names its *streamMutateError local
sme, which codespell reads as a misspelling of same/some. It is an
identifier, so exempt it beside the other variable-name entries.

Claude-Session: https://claude.ai/code/session_01BYrb2AdJSckq9FdHuqseDJ
2026-09-03 08:43:10 -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.