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Declared, Not Derived: Backup Checks That Can't Grade Their Own Homework

This series has an unusual origin story, and this post is where it pays off. Backup Verification in 2026 grew out of a comment thread under dafili 's dev.to article "My Backup Exited 0 for Three Weeks and Nothing Paged Me" — and then dafili corrected one of its claims in public, and the correction went in. Restore Drills in 2026 took his fingerprint doctrine as far as it went, and ended with an honest open question: where does the fingerprint live? I did not have his answer yet.

Now I do. He answered that question, and the follow-ups behind it, across two threads — under the backup article and under his follow-up, "Three checks that look like they passed but validated nothing" . This post is the answers, assembled into one approach.…