rustfs/docs/architecture/s3-compatibility-matrix.md

S3 Compatibility Matrix

This matrix records the user-facing S3 compatibility claim for RustFS and ties it to the executable Ceph s3tests lists under scripts/s3-tests/.

Current Claim

RustFS provides broad S3 API compatibility for supported features. It does not claim complete coverage of every standard or vendor-specific S3 behavior.

The root README should use the same wording: supported S3-compatible clients and features are covered by the compatibility matrix and test lists.

Test List Sources

List	Purpose	Current count	Source
Implemented tests	Standard S3 tests expected to pass and used by the default local s3tests run.	449	scripts/s3-tests/implemented_tests.txt
Unimplemented tests	Standard S3 features planned but not yet implemented.	17	scripts/s3-tests/unimplemented_tests.txt
Excluded tests	Vendor-specific or intentionally unsupported behavior excluded from RustFS compatibility gating.	281	scripts/s3-tests/excluded_tests.txt

Counts ignore blank lines and comments.

Supported Coverage

The implemented test list currently covers the common object-storage surface:

Area	Status	Evidence
Bucket create/delete/list/head	Supported	implemented_tests.txt
Object put/get/delete/copy/head	Supported	implemented_tests.txt
ListObjects/ListObjectsV2 prefix, delimiter, marker, max-keys	Supported	implemented_tests.txt
Multipart upload create/upload/complete/abort and selected multipart copy/checksum/object-attribute behavior	Supported	implemented_tests.txt
Bucket and object tagging	Supported	implemented_tests.txt
Bucket policy put/get/delete	Supported	implemented_tests.txt
Public access block put/get/delete	Supported	implemented_tests.txt
Presigned GET and PUT URLs	Supported	implemented_tests.txt
Range and conditional reads	Supported	implemented_tests.txt
User metadata	Supported	implemented_tests.txt
SSE-C and selected SSE-KMS edge cases	Supported	implemented_tests.txt
Selected versioning, object-lock, checksum, CORS, raw request, and conditional write behavior	Supported	implemented_tests.txt

Planned Standard Coverage

These are standard S3 areas that remain planned work and must not be described as already complete:

Area	Status	Evidence
Bucket access logging	Planned	unimplemented_tests.txt
POST Object form upload checksum handling	Planned	unimplemented_tests.txt
Bucket ownership controls	Planned	unimplemented_tests.txt
Multipart upload listing and part lookup compatibility edge cases	Not part of default gate	excluded_tests.txt
IAM-account or multi-storage-class dependent cases	Not part of default gate	unimplemented_tests.txt
Tenanted bucket policy edge cases	Needs investigation	unimplemented_tests.txt

Intentional Exclusions

excluded_tests.txt contains tests that should not block the RustFS compatibility gate. They fall into two classes:

• vendor-specific or non-portable behavior not required for RustFS S3 compatibility;
• intentionally unsupported product behavior, such as ACL authorization.

Update Rule

When a planned S3 feature is implemented, move its passing test entries from unimplemented_tests.txt to implemented_tests.txt, update this matrix, and avoid changing README wording beyond the supported coverage.