Apart from all these other products that implement s3? MinIO, Ceph (RGW), Garage, SeaweedFS, Zenko CloudServer, OpenIO, LakeFS, Versity, Storj, Riak CS,
JuiceFS, Rustfs, s3proxy.
Riak CS been dead for over a decade which makes me question the rest. Some of these also do not have the same behaviors when it comes to paths (MinIO is one of those IIRC).
Also, none of them implement full S3 API and features.
There's a difference between S3 API spec and what Amazon does with S3 - for isntance, the new CAS capabilities with Amazon are not part of the spec.
Ceph certainly implements the full API spec, though it may lag behind some changes.
It's mostly a question of engineering time available to the projects to keep up with changes.
Spec and features are intertwined. Customers who switch away from AWS S3 still want to use the same SDKs, libraries, etc that support S3 API. They don't want to rewrite their applications to use a new API. So then is it feature coverage or spec coverage?
Wrong again. Not only have I worked on DigitalOcean’s S3 implementation but I currently work on an open source product that targets S3 spec and can be used with any cloud provider and any other spec-compliant drop-in, like Garage.
We maintain a page that shows our compatibility with S3 API. It's at https://www.tigrisdata.com/docs/api/s3/. The test runner is open source at https://github.com/tigrisdata-community/s3-api-compat-tests