When it comes to pure file synchronization and transfer speeds, Seafile often dramatically outperforms solutions like Nextcloud. The best part? The Professional Edition of Seafile is free for up to 3 users and natively supports S3 object storage backends.

In this tutorial, you’ll learn how to set up Seafile Pro using Docker Compose and offload your data sheets, file histories (commits), and blocks to an affordable S3 bucket (e.g., Hetzner Storage Box, AWS, Wasabi).

Important Note: Native S3 backend support is officially a feature of the Seafile Pro Edition and is not present in the Community Edition (CE). Since the Pro version is free for small teams or solopreneurs (up to 3 users), we will explicitly use this version for our setup.

Prerequisites

  • A cloud VPS (running Ubuntu 22.04 or 24.04).
  • Docker & Docker Compose installed.
  • S3 Credentials: A clean, empty S3 bucket (bucket_name, endpoint_url, access_key, and secret_key).
  • A domain correctly pointing to your server’s IP via DNS.

Step 1: The Docker Compose Setup

Create a working directory ~/seafile-s3 and move into it. Create your docker-compose.yml:

version: '2.0'
services:
  db:
    image: mariadb:10.11
    environment:
      - MYSQL_ROOT_PASSWORD=A_Very_Secure_Password
      - MYSQL_LOG_CONSOLE=true
    volumes:
      - /opt/seafile-mysql/db:/var/lib/mysql

  memcached:
    image: memcached:1.6
    entrypoint: memcached -m 256

  elasticsearch:
    image: seafileltd/elasticsearch-with-ik:5.6.16
    environment:
      - discovery.type=single-node
      - bootstrap.memory_lock=true
      - "ES_JAVA_OPTS=-Xms1g -Xmx1g"
    ulimits:
      memlock:
        soft: -1
        hard: -1
    volumes:
      - /opt/seafile-elasticsearch/data:/usr/share/elasticsearch/data

  seafile:
    image: docker.seadrive.org/seafileltd/seafile-pro-mc:latest
    environment:
      - DB_HOST=db
      - DB_ROOT_PASSWD=A_Very_Secure_Password
      - TIME_ZONE=Europe/Zurich
      - SEAFILE_ADMIN_EMAIL=admin@yourdomain.ch
      - SEAFILE_ADMIN_PASSWORD=Secure_Admin_Password!
      - SEAFILE_SERVER_LETSENCRYPT=false   # Handled by a Reverse Proxy
      - SEAFILE_SERVER_HOSTNAME=seafile.yourdomain.ch
    ports:
      - "8080:80"
    volumes:
      - /opt/seafile-data:/shared
    depends_on:
      - db
      - memcached
      - elasticsearch

Start the stack briefly (docker compose up -d), wait about 2-3 minutes for the admin account to be generated, and then stop it again (docker compose down). This forces Seafile to generate the default configuration files we need to edit.

Step 2: Configuring seafile.conf for S3

Seafile handles data using “blocks”, file histories (“commits”), and file systems (“fs”). To push these straight to your S3 bucket, edit the file located at /opt/seafile-data/seafile/conf/seafile.conf and append the following:

[commit_object_backend]
name = s3
bucket = your-seafile-bucket
key_id = YOUR_ACCESS_KEY
key = YOUR_SECRET_KEY
use_v4_signature = true
aws_region = eu-central-1
host = s3.eu-central-1.amazonaws.com # Customize for Hetzner, MinIO etc.
path_style_request = true

[fs_object_backend]
name = s3
bucket = your-seafile-bucket
key_id = YOUR_ACCESS_KEY
key = YOUR_SECRET_KEY
use_v4_signature = true
aws_region = eu-central-1
host = s3.eu-central-1.amazonaws.com
path_style_request = true

[block_backend]
name = s3
bucket = your-seafile-bucket
key_id = YOUR_ACCESS_KEY
key = YOUR_SECRET_KEY
use_v4_signature = true
aws_region = eu-central-1
host = s3.eu-central-1.amazonaws.com
path_style_request = true

Step 3: Launch & Reverse Proxy

Fire up the containers again with docker compose up -d. Seafile is now routing your heavy data loads straight to the S3 bucket! The local storage directory (/opt/seafile-data) will now only be used for caching, the relational database, and small structural metadata. You will no longer run out of local storage!

As a final measure, make sure to funnel the internal port 8080 through an SSL-featured Reverse Proxy (like Caddy or Traefik) to provide a secure HTTPS environment for your app.

Conclusion

By orchestrating Seafile Pro alongside S3, you get an endlessly scalable, lightning-fast file sync service. No more VPS migrations just because you ran out of disk capacity! If you need technical assistance with similar infrastructures or Corporate IT integrations, do not hesitate to contact me!