Verify-on-read re-hashes the full object on every local read (~8x slower than write). A ReadVerifier seam skips re-verification for blobs verified this process, while scrub still catches bitrot.
Phase-0 profiling harness via go test -cpuprofile/-memprofile; Rule 75 forbids networked pprof on unauthenticated listeners. The baseline proved stdlib SHA-256 already uses AVX2.
Adaptive behaviors use compile-time Go interface seams injected at decision points — not dynamic plugins. The fast path stays concrete; the trust core stays auditable; policy is declarative.
Prometheus metrics export with a per-node metrics_host/metrics_port bind — observability that scales past the ‘just scrape node 0’ era.
R5 Phases 2-4 shipped: storage metrics (disk, CAS, GC), P2P metrics (SWIM, leases, scatter-gather), and opt-in latency histograms — all with <1% overhead via sync/atomic counters.
CAS keys make verify-on-read free: central verification, x-amz-checksum echo, tombstone GC, and corruption surfacing.
S3 integrity checksums moved from a surface-level adapter into the storage/ingest core via a protocol-agnostic ChecksumProvider seam — every write path verified, replicas re-verify on receive.
S3 ListObjectsV2 XML serialization dropped from ~1000 allocations to 16 per op via inlined time formatting and a pre-allocated escape buffer.
Three adaptive feedback loops: gossip fanout scales with cluster size, streaming chunk size adapts to cipher/memory, peer quality feeds quorum decisions.
The Bolt mindset codified: no heap escapes in hashing/encoding, deadline amortization cuts SetDeadline ~98%, allocation hotspots hunted by profile. Teaches: zero-escape patterns, measurement contracts, trade-off posture.