walsync

Lightweight SQLite WAL sync to S3/Tigris.

Like Litestream but:

• ~7MB binary (vs Litestream's runtime overhead)
• Watch multiple databases at once
• Minimal memory footprint (~5-10MB RSS)

Installation

cargo install walsync

Quick Start

# Watch databases and sync to S3
walsync watch db1.db db2.db -b s3://my-bucket/backups

# With Tigris endpoint
walsync watch app.db -b s3://my-bucket --endpoint https://fly.storage.tigris.dev

# Take immediate snapshot
walsync snapshot app.db -b s3://my-bucket

# List backed up databases
walsync list -b s3://my-bucket

# Restore database
walsync restore mydb -o restored.db -b s3://my-bucket

How It Works

Local:                          S3:
app.db                          /app/snapshots/20240110120000.db
app.db-wal  ────────────────►   /app/wal/00000001-20240110120001234.wal
           (file watcher)       /app/wal/00000001-20240110120005678.wal
                                /app/state.json

1. Watch - Monitor WAL files for changes (inotify/kqueue)
2. Sync - Upload new WAL frames to S3 incrementally
3. Snapshot - Periodic full database snapshots (configurable interval)
4. Restore - Download snapshot + replay WAL segments

Commands

walsync watch

Watch databases and continuously sync WAL changes.

walsync watch <DATABASES>... -b <BUCKET> [OPTIONS]

Options:
  --snapshot-interval <SECS>  Snapshot interval (default: 3600)
  --endpoint <URL>            S3 endpoint (for Tigris/MinIO)

walsync snapshot

Take an immediate snapshot.

walsync snapshot <DATABASE> -b <BUCKET>

walsync restore

Restore a database from S3.

walsync restore <NAME> -o <OUTPUT> -b <BUCKET>

Options:
  --point-in-time <ISO8601>  Restore to specific time

walsync list

List backed up databases.

walsync list -b <BUCKET>

Environment Variables

• AWS_ACCESS_KEY_ID - AWS/Tigris access key
• AWS_SECRET_ACCESS_KEY - AWS/Tigris secret key
• AWS_ENDPOINT_URL_S3 - S3 endpoint (for Tigris/MinIO)
• AWS_REGION - AWS region (default: us-east-1)

S3 Layout

s3://bucket/prefix/
├── dbname/
│   ├── snapshots/
│   │   ├── 20240110120000.db
│   │   └── 20240110130000.db
│   ├── wal/
│   │   ├── 00000001-20240110120001234.wal
│   │   ├── 00000001-20240110120005678.wal
│   │   └── ...
│   └── state.json
└── otherdb/
    └── ...

Use with Tenement/Slum

Perfect for backing up tenant SQLite databases:

# In your tenement deployment
walsync watch \
  /var/lib/ourfam/romneys/app.db \
  /var/lib/ourfam/smiths/app.db \
  /var/lib/ourfam/jones/app.db \
  -b s3://backups/ourfam \
  --endpoint https://fly.storage.tigris.dev

License

Apache 2.0