Best Free & Open Source Alternatives to RustFS

SeaweedFS is a distributed storage system designed to handle billions of files with O(1) disk access and effortless horizontal scaling. It provides S3-compatible object storage, a POSIX-compliant file system, and Iceberg table support.

Key Features

• S3 Compatible API - Full S3 API support for object storage workloads.
• Distributed File System - POSIX-compliant filer with FUSE mount support for seamless file access.
• Massive Scale - Designed for billions of files with O(1) disk access time.
• Erasure Coding - Built-in data redundancy without the overhead of full replication.
• Tiered Storage - Hot and cold storage tiers with automatic data migration.\n- FUSE Mount - Mount SeaweedFS as a local file system on any machine.
• Hadoop HDFS Compatible - Drop-in replacement for HDFS in big data workloads.
• Iceberg Tables - Native support for Apache Iceberg table format.
• Replication - Cross-datacenter replication for disaster recovery.
• Kubernetes Native - Helm charts and operators for easy K8s deployment.
• Web UI - Built-in web interface for file browsing and management.

Architecture

SeaweedFS uses a master-volume-filer architecture. The master server manages volume assignments, volumes store actual data with O(1) lookup, and the filer provides a directory structure on top. This separation allows independent scaling of metadata and data.

Self-Hosting

SeaweedFS can be deployed as a single binary or via Docker. It supports standalone, replication, and erasure coding modes for different reliability requirements.

VersityGW is a high-performance S3 translation gateway that bridges S3-reliant applications with existing storage systems. It translates incoming S3 API requests into equivalent operations on various backend storage systems.

Key Features

• S3 Compatible - Full S3 API compatibility as a translation layer.
• Multiple Backends - Supports POSIX filesystem, ScoutFS, Azure Blob Storage, and other S3 servers.
• Stateless - Multiple instances can be deployed in a cluster for increased throughput.
• Static Website Hosting - Serve S3 buckets as static websites with index documents, custom error pages, and routing rules.
• Web GUI - Optional web interface for administration and file exploration.
• Cross-Platform - Runs on Linux, macOS, BSD, and Windows.
• Lightweight - Simple single-binary deployment.
• POSIX Compatibility - Access files via both POSIX and S3 protocols simultaneously.

Architecture

VersityGW is completely stateless - any request can be serviced by any gateway instance. This allows horizontal scaling behind load balancers for optimal performance. The gateway translates S3 operations to backend-specific calls.

Self-Hosting

Deploy with a single command to turn your filesystem into an S3 server. Multiple backend options allow integration with existing storage infrastructure.

Alarik is a high-performance, S3-compatible object storage system built in Swift. It was created in response to concerns around MinIO's licensing and community direction, offering a fully open-source (Apache 2.0) alternative focused on speed, simplicity, and transparency.

Key Features

• Full S3 API compatibility - Put, Get, Head, Delete, Copy, multipart uploads, versioning, presigned URLs, object tagging, bucket policies, and lifecycle rules.
• Web console - Drag-and-drop uploads, recursive search, metadata editing, versioning UI, shared links, and an admin dashboard with live metrics.
• Authentication - Local accounts, OIDC SSO, S3 access keys, and bucket-level policies.
• Webhooks - AWS-compatible event notifications with HMAC-signed deliveries and reliable outbox-based retry.
• Bucket replication - SigV4-signed replication to any S3-compatible target, with sync or async delivery per rule.

Self-Hosting

Alarik is designed to be self-hosted. It provides Docker images and a straightforward deployment model. The project targets teams that need a fast, self-hosted S3 store without vendor lock-in or licensing surprises.

S4Core is an open-source, S3-compatible object storage server written in Rust. It claims to be 3x faster than MinIO and RustFS while solving the inode exhaustion problem through append-only log storage.

Key Features

• Full S3 API Compatibility - Works with AWS CLI, boto3, and any S3-compatible client.
• Inode Problem Solved - Append-only volume files eliminate inode exhaustion (1 billion objects = ~1000 files).
• Content Deduplication - Automatic deduplication saves 30-50% storage space.
• S3 Select SQL - Query CSV/JSON/Parquet objects with full SQL powered by Apache DataFusion, including multi-object glob patterns.
• Object Versioning - S3-compatible versioning with delete markers and lifecycle policies.
• Atomic Operations - Rename directories with millions of files in milliseconds.
• IAM & Admin API - Role-based access control (Reader, Writer, SuperUser) with JWT authentication.
• Federation - Leaderless quorum replication for high availability (N=3, W=2, R=2).
• Strict Consistency - Data is guaranteed to be written before returning success.

Architecture

S4Core uses a Bitcask-style storage approach with append-only volume files (~1GB each) and metadata stored in fjall (LSM-tree, MVCC, LZ4 compression). This ensures minimal inode usage, maximum write performance, atomic metadata operations, and fast crash recovery.

Self-Hosting

Available as Docker images (Community and Enterprise editions) or can be built from source with Rust. The CE edition supports single node or up to 3-node clusters with quorum replication.

Garage is an S3-compatible distributed object storage service designed for self-hosting at a small-to-medium scale. It is built for clusters of nodes at different physical locations, providing geo-replicated storage that stays available even when some servers are unreachable.

Key Features

• S3 Compatible - Full S3 API compatibility for object storage workloads.
• Geo-Distributed - Designed for multi-location deployments with automatic data replication across nodes.
• Lightweight - Easy to operate and highly resilient to machine failures.
• Self-Hosted - Built by Deuxfleurs, an experimental self-hosted service provider, in production since 2020.
• Rust Performance - Memory-safe, high-performance implementation in Rust.
• Flexible Replication - Configurable replication factor per bucket.
• Anti-Entropy - Background repair mechanisms to maintain data consistency across nodes.

Architecture

Garage uses a distributed architecture with gossip-based membership, consistent hashing for data placement, and a local LMDB database for metadata. Each node manages its own data, and Garage handles replication and consistency automatically.

Self-Hosting

Garage is designed for self-hosting. It can be deployed as a single binary with minimal configuration. The project provides Debian packages, Nix packages, and Docker images.

HS5 is a high-performance, scale-up, self-hosted S3-compatible object storage service. It is designed for single-node deployments where you can leverage powerful machines with terabytes of RAM and storage.

Key Features

• S3 Compatible - Full AWS S3 API compatibility.
• High Performance - Optimized for maximum single-node throughput using C++.
• Scale-Up Architecture - Runs on a single powerful machine rather than distributing across nodes.
• Simple Deployment - Easy to set up and run with minimal configuration.
• Web Interface - Built-in web UI for bucket management and user configuration.
• DuckDB Integration - Query S3 data directly using SQL via DuckDB.
• Durability Guarantees - Robust data persistence with manual commit mode option.
• Lightweight - Minimal resource overhead compared to distributed alternatives.

When to Use HS5

HS5 is ideal when you need high-performance S3 storage on a single powerful machine. It is simpler to operate than distributed alternatives like MinIO or SeaweedFS, and avoids the memory overhead of keeping indexes entirely in RAM.

Self-Hosting

HS5 is designed for self-hosting. Deploy as a single binary on a powerful server. Licensed under LGPLv3+, making it free for commercial use.