Open-Source Object Storage

Choose the system your team can recover, upgrade and afford to operate.

Backups, application files, datasets and models can share an S3 interface without sharing the same operational needs. Here is where I would start, and what would rule each option out.

Sources reviewed: 2026-09-05. My assessment uses official repositories, releases and documentation, not a first-hand benchmark or certification. The production checks below remain requirements, not completed tests.

Comparison at a glance

Here, Silo means PGSTY's independent MinIO fork, not another project or hosted service with the same name.

The table compares the open-source server, not a vendor's commercial edition. Project links lead to primary repositories; version and operational notes follow below. No row is a universal winner.

The license names identify the reviewed server code. They do not describe every dependency, packaged component or commercial offering. Ceph's COPYING file lists its LGPL choice and file-specific exceptions. Review the exact distribution's terms as part of adoption; free of charge and open source are not synonyms.

Start with the workload

For a small new installation, I would compare Garage and SeaweedFS first. If a protected filesystem already exists, Versity Gateway is another small-footprint candidate: it adds an S3 interface, not a new durability layer. For an existing MinIO deployment, Silo addresses continuity, but the upgrade path still needs rehearsal. Ceph, Ozone and Swift belong on the list when their broader platform model is useful, not simply because they can expose S3. RustFS is a release candidate, while the original MinIO community repository is archived. An S3-compatible endpoint does not promise every Amazon S3 feature or identical behavior under failure.

• A small application or a few independent sites: start with Garage if its simpler bucket/key permissions and lack of versioning fit. Compare SeaweedFS when a file interface or its filer model is useful. One process on one disk can be convenient; it is not high availability.
• Backups that must resist deletion: do not choose from a successful upload test. Require the backup client's supported Object Lock semantics, retention enforcement and a restore rehearsal. Garage is not a fit when S3 Object Lock is mandatory; Ozone's documented S3 gaps also exclude it.
• An existing MinIO installation: evaluate Silo on a recoverable copy with the exact source version, topology, encryption and client set. Retain a verified recovery path before changing any production binary.
• A private-cloud storage platform: start with Ceph RGW if the team already operates Ceph or needs its wider storage services. Keep Swift where the organization already owns Swift's operational model. Neither justifies a new storage team for one small bucket.
• A data lake or AI workload: compare SeaweedFS and Ceph against the actual readers, writers and catalog. Add Ozone for a Hadoop-centered environment. An S3 endpoint alone does not implement Iceberg transactions, catalog authorization or a complete training data pipeline.

Other layers and candidates to watch

These projects are relevant to the decision, but they do not all replace a distributed object store. Separating the layers avoids comparing an interface with the system responsible for keeping the bytes safe.

• Existing filesystem: Versity Gateway 1.8.0 (Apache-2.0; released 2026-09-04) translates S3 to POSIX, ScoutFS, Azure or another S3 backend. This is my small-installation candidate when the filesystem, backups and recovery are already owned. Its POSIX versioning directory is not automatic disk redundancy or a separate backup.
• Specialized data platforms: NVIDIA AIStore (MIT) combines native storage, remote data access and configurable caching for data-intensive workloads. CubeFS 3.6.0 (Apache-2.0) combines distributed file and object interfaces. Consider them for the wider data path or filesystem requirement, not as the default answer to a small S3 bucket. Pin the matching release documentation.
• S3 interface over other backends: CloudServer 9.4.3 and S3Proxy 4.1.0 (Apache-2.0) can bridge applications to existing storage. Evaluate the backend's durability and the gateway's compatibility separately; running an interface is not operating the full commercial Scality platform.
• Disposable development and CI: local-s3 (MIT) deliberately targets quick local tests. That can be the simplest option for this purpose, not for production durability or replication.
• Early candidates: Alarik and FractalBits (Apache-2.0) identify themselves as beta. Keep them on an evaluation list; claimed performance or feature counts do not replace recovery, security and upgrade evidence. They are not promoted above maintained alternatives solely because they are newer.

Version and operational notes

Expand a project for the source boundary behind its recommendation. A recent release is evidence of activity, not proof of reliability for your workload.

Before using private-cloud data

Use a disposable environment with the intended topology and client versions. Write acceptance criteria before measuring anything:

1. Compatibility: upload, list, range-read, copy and delete; interrupted multipart uploads; presigned URLs; checksums and conditional writes. Exercise Unicode keys, metadata and the backup or lakehouse client itself. A successful PutObject is not an S3 conformance test.
2. Security: deny anonymous and cross-tenant access, rotate credentials, isolate admin/internal endpoints and test TLS and key recovery. If required, test retention and legal hold with both application and privileged roles. Private hosting alone establishes neither isolation nor compliance.
3. Recovery: lose a disk, node and metadata service; fill capacity; break a network link; then restore to a clean deployment from an independent copy. Compare bytes, versions, metadata and permissions. Record tolerated data loss and restore time; replication alone is not that evidence.
4. Upgrade and exit: pin server/client versions and artifact digests. Exercise the supported upgrade path and a recovery route if downgrade is unsupported. A copy job may omit versions, retention or policy metadata. Do not mount a different engine on live disks without explicit support.
5. Cost under failure: measure the real object-size distribution, request mix, concurrency and tail latency during repair, not only steady state. Count usable capacity after replicas/parity, spare space, RAM, network, power, independent backups and the people handling incidents.

If no one owns those checks and the recovery procedure, a managed object service is a valid baseline even when self-hosting initially looks cheaper. Revisit this comparison when a release, maintenance policy, S3 requirement or failure test changes the shortlist.