New encrypted writes store a keyed HMAC fingerprint as the object ETag
(docs/operations/encrypted-etags.md). Replication forwards that ETag on
x-rustfs-source-etag, but a target that computes its own ETag (AWS S3 and
most compatible stores) answers the plaintext PUT with the MD5 of what it
received. Both values are 32 hex characters, so verify_single_part_replica
treated the fingerprint as a comparable MD5 and failed every single-part
SSE-S3 / SSE-KMS replica with "replica etag mismatch"; MRF and resync then
retried the object forever. RustFS and MinIO targets adopt the source ETag
and were unaffected.
Exempt sources whose stored ETag cannot describe the wire bytes: any
managed-SSE or SSE-C source, decided by the existing replication
source-encryption classifier. The checksum header on the replication PUT
remains the integrity check for those objects; plaintext sources keep the
audit unchanged.
Claude-Session: https://claude.ai/code/session_01CezCdjE9AdShFUi9tNk797
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>
Chris
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