Hands-on comparison: six open-source alternatives to MinIO for local S3

A hands-on comparison published on rmoff.net and picked up on the Hacker News front page pits six open-source projects against MinIO for a narrow but common job: single-node, S3-compatible object storage that drops into an existing Docker Compose stack. The method was deliberately minimal — take a working project built around MinIO and swap in each alternative with as few changes as possible, keeping MinIO's mc client in place since tools such as s3cmd or the AWS CLI can replace it later.

The easy drop-ins

S3Proxy, tested at version 3.0.0, comes off well. It is Apache 2.0-licensed, its Docker image has passed five million pulls, and the author found it very easy to implement and pleasantly lightweight. One caveat: it builds on jclouds, a project the Apache Software Foundation moved to the Attic, meaning retired, in mid-2025 — probably a non-issue if you only ever use local storage.

RustFS, at 1.0.0-alpha.79, was the simplest of the lot to configure and ships with a GUI. It is also the least mature: an alpha release with a Docker image at over 100k pulls, and a recent serious security vulnerability that has put some potential users off. According to rmoff.net, the project's website has the feel of fresh paint, with several links resolving to the same page — something that may matter less for demos if switching away again is cheap.

SeaweedFS, tested at 4.06, was a fairly straightforward image swap. The one extra step was a separate auth configuration file, which the author inlined into the Compose file; shortly after the post went up, the project reportedly replied that it would remove that requirement entirely. It is Apache 2.0-licensed, includes a basic UI, and is long-established, with S3 support since the 0.91 release in 2018. Its website reads more like a commercial product — fronted by the name SeaweedFS Enterprise with a pricing option and no obvious GitHub link — but it is an open-source project underneath.

Zenko CloudServer, tested at 9.2.8 and formerly known as S3 Server, is part of the Zenko toolset published by Scality. It replaces MinIO easily enough, though the author found it initially tricky to disentangle the names — cloudserver, zenko, scality — to work out what to actually run, and noted the documentation links to an outdated Docker image.

The heavyweight end

Garage, at version 1.0.0, works but earned the harshest verdict on configuration. Licensed under AGPL, it needed a second container just to handle initial setup plus a TOML config file, and access keys must follow a strict format starting with GK followed by twelve hex-encoded bytes. The author needed a friend's help to get it running and describes it as excellent production hygiene but overkill for local demos — a capable system, just not a drop-in replacement.

Apache Ozone, tested at 2.1.0, spun out of Hadoop in 2020 after starting life inside the HDFS project in 2015. It functions as a MinIO replacement but is far from lightweight: neither the author nor Claude could work out how to deploy it with fewer than four nodes. Ceph Object Gateway is grouped with Ozone as capable at what it does, but neither is a container you casually slot into a Compose stack for local development.

The post itself concedes the framing is not a fair appraisal of Garage or Ozone as technologies — distributed systems naturally carry a steeper configuration curve — but the stated requirement was specifically a simple MinIO stand-in.

Why it matters

Local S3-compatible storage is a quiet dependency of a huge number of development setups, integration tests and demos, and this comparison shows the alternatives are not interchangeable. Licence terms differ (Apache 2.0 versus AGPL), maturity varies from a battle-tested 2018-era project to an alpha with a recent vulnerability behind it, and setup effort ranges from a one-line image swap to multi-node cluster plumbing. For anyone re-evaluating a single-node MinIO dependency, S3Proxy, SeaweedFS and Zenko CloudServer emerge as the low-friction options, while Garage and Ozone are better treated as their own projects rather than substitutes.