Replay as a standing control
One baseline snapshot plus an append-only change log reconstructs any historical state.
A reconciliation job replays the log every day and diffs the result against the export
actually received — 100% match on 56,265 records across AE, MH, CM, VS, and DM, on every
date with source data. Replay fidelity is not a one-time claim; it is a daily automated check.
The storage math
Full daily snapshots would have cost roughly 7 GB over the 35-day validation window.
Baseline plus deltas came to about 250 MB — a ~96% reduction with complete data fidelity
and field-level change history retained. The monitor demo reproduces the mechanism at toy scale.
Evidence by construction
Validation deliverables (IQ/OQ/PQ, traceability, release records) map to scripted health
checks and automated suites that run on every release, with daily SHA-256-manifest backups
and rehearsed restores. Governance survives audits because it produces its evidence as a
side effect of running.