Day 36 — Separate identity readiness, artifact integrity and the business target
Learning task. Select a recovery candidate using the current approved service state rather than the most reassuring artifact label. Recovery involves several independent predicates: the copy has expected bytes; its contents represent the desired transaction history; the application can use it; identity dependencies function through permitted paths; and the owner accepts the tested outcome. None of these predicates implies all the others. A successful backup digest comparison can coexist with a harmful whole restore.
First advance the case in order. C25, released 10:11, records a distinct 10:08 identity/service-owner approval to remove the unapproved recovery method, make a scoped credential change and revoke s-77. The authorized identity operator reports completion at 10:10; a fresh IdP status query at 10:11 finds s-77 inactive. Separate operation report from status observation. The specific method/session work does not establish that every other session, recovery option or copied credential is absent. Nor does it establish that the legitimate scheduled job can use its updated authentication path. That service dependency needs its own check; undoing the credential change to make a failed restart work would require a new decision.
Next inspect C26 at 10:12: the documented 08:30 snapshot matches the supplied digest baseline, and an isolated read shows S40/S41/S42 all open. The scoped current values are S40/S41 reserved, S42 unavailable; the owner target retains the valid reservations and sets S42 open. The later legitimate S40/S41 work changes the restore decision. The digest cannot decide which transactions should survive. A comparison also needs the named baseline and source context: an equal hash does not independently authenticate the source, prove capture completeness or turn a stale business state into current intent.
Worked comparison. Whole snapshot restore would correct the supplied S42 value while undoing two approved reservations. Do-nothing retains S40/S41 but leaves the current S42 problem. Targeted reconciliation is therefore the preferred candidate in this scoped comparison: change S42 toward owner-approved intent, preserve correct slots and test the application transaction. It still needs a fresh version precondition, evidence preservation, isolated route/audit checks, production authority and rollback. Do not generalize this into “small writes are always safe.” A real enrollment transaction may update capacity, reservations, retry state, audit and notifications together; a raw single-field edit could violate those invariants even while the three visible values look right.
Contrast. “The hash matches, so restore everything and mark access clean” combines a byte comparison with two unsupported conclusions. C26's intact copy is the wrong whole-business target, and C25's one-session result does not close identity discovery. The correct ledger lists copy validity, candidate value differences, business authority, service/authentication checks and unresolved source coverage separately. The snapshot remains useful as a preserved reference; rejecting wholesale use does not mean rejecting backups.
Offline practice and result. Run §8.3 unchanged. Its first line names S40:open->reserved, S41:open->reserved; its second names S42:unavailable->open. These are differences from the supplied target, not a list of authorized commands or all database discrepancies. On paper, add permission, service cost, rollback dependency and unknowns for each candidate. Explain why snapshot age is not automatically lost-transaction duration when later valid changes are preserved by reconciliation.
Limits and decision. At 10:12 there is no C27 test result, production approval or completed restart. Submit EX036 and compare the worked answer. Carry a conditional candidate and explicit acceptance criteria to the next lesson; do not carry a restoration receipt that does not exist.
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Exercise for this lesson
EX036 — Candidate comparison. Objective: distinguish specific identity readiness, artifact integrity and business correctness. Inputs: C13/C25/C26 through 10:12 and Day 36. Compare whole snapshot, do-nothing and targeted reconciliation across S40/S41/S42, service/authentication dependencies, authority, version and rollback. Record C25 approval/report/status separately and its discovery limit. Explain why matching bytes and snapshot age do not prove correct business target or actual data loss; no later test or production receipt is available. Rubric: 0 = full restore justified by hash alone, invented identity closure or operation; 1 = correct three candidates but incomplete source/authority/service limits; 2 = scoped target/loss ledger and conditional reconciliation with independent identity checks. Worked answer.