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.	452	`scripts/s3-tests/implemented_tests.txt`
Lifecycle behavior tests	Expiration behavior cases gated by the dedicated `s3-lifecycle-behavior-tests` lane (debug-accelerated day + scanner enabled).	5	`scripts/s3-tests/lifecycle_behavior_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.	273	`scripts/s3-tests/excluded_tests.txt`

Counts ignore blank lines and comments.

The lifecycle behavior lane runs real Days-based expiration cases that need RUSTFS_ILM_DEBUG_DAY_SECS (Ceph lc_debug_interval equivalent) and an enabled background scanner; it cannot share the default single-server gate because a global debug day would also shrink the x-amz-expiration header asserted by the test_lifecycle_expiration_header_* cases. See scripts/s3-tests/run.sh (IMPLEMENTED_TESTS_FILE override) and the s3-lifecycle-behavior-tests job in .github/workflows/ci.yml.

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`
CopyObject checksums (CRC32, CRC32C, CRC64NVME, SHA1, SHA256, MD5, SHA512, XXHASH3, XXHASH64, XXHASH128), including source preservation and explicit override	Supported in the first RustFS release containing this change	`crates/e2e_test/src/copy_object_checksum_test.rs`
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`

"Supported" for the SSE row means RustFS encrypts and decrypts its own objects. It does not mean RustFS can read objects another implementation encrypted: objects MinIO wrote with SSE-S3, SSE-KMS, or SSE-C are not readable by RustFS today, which matters when migrating. See MinIO file-format interoperability, Part C and rustfs/backlog#1638.

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.