Oh heh, a trip down the memory lane. I wrote the initial version of that, in an era where AWS docs did not match observed S3 behavior. The only way to make an S3-compatible API was to create a suite of over-the-network tests to run against both AWS S3 and radosgw.

We also had a little grammar-based fuzzer for S3 requests (really, any HTTP), but over the last 10+ years I've lost track of what happened to that code. That found some incompatibilities with allowed character sets etc too.

> I believe you're forced to have your data backed by a Ceph OSD.

It makes perfect sense as this is a feature of Ceph.

> Whereas Minio can point to an NFS share on a NAS.

Eh, different trade-offs.

Minio used to be able to do this, but they dropped this feature - "gateway mode" - several years ago.