ConfigsApr 15, 2026·3 min read

SeaweedFS — Distributed Object, File, and S3 Storage

Fast distributed storage system for blobs, files, S3 API, and even Iceberg tables, designed to handle billions of files with O(1) disk access.

TL;DR
SeaweedFS handles billions of files with O(1) disk access, S3 API compatibility, and simple single-binary operation.
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What it is

SeaweedFS is a fast distributed storage system designed to handle billions of files efficiently. It provides an S3-compatible API, a POSIX-like filer for hierarchical file access, and a volume server for raw blob storage. The architecture uses O(1) disk seeks for file lookups, making it fast regardless of how many files are stored.

SeaweedFS is designed for teams that need to store and serve large volumes of files (images, documents, logs) without the complexity and cost of cloud object storage.

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How it saves time or tokens

Cloud object storage charges per request, per GB stored, and per GB transferred. SeaweedFS provides S3-compatible storage that you host yourself, eliminating per-request costs entirely. For applications that store millions of small files, the O(1) lookup architecture means consistent performance where traditional filesystems slow down as file counts grow. Deployment is a single binary, not a complex cluster of services.

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How to use

  1. Download and start a single-node server:
wget https://github.com/seaweedfs/seaweedfs/releases/latest/download/linux_amd64_full.tar.gz
tar xzf linux_amd64_full.tar.gz

# Start master + volume + filer + S3 + WebDAV
./weed server -s3 -filer
  1. Upload a file via S3 API:
aws --endpoint-url http://localhost:8333 s3 cp report.pdf s3://mybucket/report.pdf
  1. Or use the HTTP API directly:
curl -F file=@photo.jpg http://localhost:9333/submit
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Example

Using SeaweedFS S3 API with Python boto3:

import boto3

s3 = boto3.client(
    's3',
    endpoint_url='http://localhost:8333',
    aws_access_key_id='any',
    aws_secret_access_key='any',
)

# Create bucket
s3.create_bucket(Bucket='images')

# Upload file
s3.upload_file('photo.jpg', 'images', 'photo.jpg')

# List objects
response = s3.list_objects_v2(Bucket='images')
for obj in response.get('Contents', []):
    print(obj['Key'], obj['Size'])
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Related on TokRepo

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Common pitfalls

  • Running only a single volume server in production. For durability and availability, deploy multiple volume servers with replication. SeaweedFS supports rack-aware and data-center-aware replication.
  • Not configuring the filer for your access pattern. The default filer stores metadata in LevelDB. For production, use an external database like MySQL, PostgreSQL, or etcd for filer metadata.
  • Ignoring compaction. SeaweedFS volumes accumulate deleted file space over time. Run periodic compaction to reclaim disk space.
  • Starting with an overly complex configuration instead of defaults. Begin with the minimal setup, verify it works, then customize incrementally. This approach catches configuration errors early and keeps troubleshooting straightforward.

For teams evaluating this tool, the time saved on initial setup alone justifies the adoption. The well-documented API and active community mean most common questions have already been answered, reducing the learning curve and the number of tokens spent explaining basic usage to AI assistants.

Frequently Asked Questions

How does SeaweedFS achieve O(1) file lookups?+

SeaweedFS stores files in fixed-size volumes. Each file's location is determined by its volume ID and offset, which are stored in a lightweight in-memory map. Looking up any file requires exactly one disk seek regardless of the total number of files.

Is SeaweedFS compatible with AWS S3?+

Yes. SeaweedFS implements the S3 API, supporting common operations like PutObject, GetObject, ListObjects, multipart upload, and bucket policies. Most S3 client libraries (boto3, aws-cli, mc) work with SeaweedFS without modification.

How does SeaweedFS handle replication?+

SeaweedFS supports synchronous replication with configurable placement policies: same rack, different racks, or different data centers. You specify the replication strategy when creating volumes, and the master server enforces it.

Can SeaweedFS replace MinIO?+

Both provide S3-compatible object storage. SeaweedFS excels at handling billions of small files due to its O(1) lookup architecture. MinIO is more focused on S3 API completeness and erasure coding. Choose based on your primary access pattern.

Does SeaweedFS support encryption?+

SeaweedFS supports encryption at rest for stored data. You enable it in the volume server configuration. For encryption in transit, put SeaweedFS behind a TLS-terminating reverse proxy or use the built-in TLS support.

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