LEARN. PRACTICE. GROW.Define the basis for proceeding
A cutover window needs both a sequence and decision criteria. In the fictional scenario, reopening requires runtime, functional flow, integrity, access, dependencies, and service ownership. These criteria are cumulative; five passing outcomes do not cancel a data discrepancy. The checklist prepares discussion but is not automatic authorization. Record available evidence, gaps, impact, and who may decide. Distinguish moving to the next stage, accepting limited scope, and declaring full service availability. Each decision can require different results and needs precise communication so that downstream teams understand what they may rely upon.
Reserve complete return time
In a one-hundred-and-fifty-minute window, returning to the previous state takes thirty-five, validation fifteen, and agreed reserve ten. Total budget is sixty; the latest start preserving it is minute ninety. At minute eighty-five only five minutes of margin remain. Another ten-minute investigation exceeds that margin even if it looks short compared with the whole window. The decision should show effects on consumers and remaining options. Extending the window or consuming reserve requires explicit authority and impact rather than silently changing the calculation to make the forecast look acceptable.
Reconcile beyond totals
The model has three source records: A100, B200, and C300. Destination contains A100, B250, and D250. Both have three rows and total six hundred; however, C is missing, D appears, and B changed. Comparing by reference exposes all three differences. For real data, define keys, scope, fields, and equivalence rules before comparison. Also control relationships across sets: a database restored later than its archive may reference files that do not exist. Valid checksums for individual backups do not by themselves establish functional consistency across recovered data sets.
Separate the data point from recovery duration
On the synthetic clock, interruption occurs at minute one hundred and eighty. The recoverable point is one hundred and sixty-eight although the backup file finished at one hundred and seventy-eight. Data lag is twelve minutes rather than two. Against a fifteen-minute RPO, that outcome meets the stated set’s limit. If service becomes usable seventy minutes later against a sixty-minute RTO, the time objective missed by ten. Present both outcomes and recovered scope separately. Meeting one objective does not automatically compensate for missing the other or establish integrity of every dependent data set.
Handle writes after the cut
After opening the destination, new instructions can produce effects absent from the old copy. Returning to previous binaries and restoring that copy does not demonstrate correct return. Identify the set accepted after the cut, authoritative source, unknown states, and authorized reconciliation method. If the previous version cannot read the new schema, compatibility also needs resolution. The plan may choose destination recovery or return with transformation and reconciliation, but it must preserve business outcomes. The exercise sends no instructions and tests no banking system; it prepares questions and acceptance criteria for authorized work.
Hand evidence to the shift and committee
The final report should distinguish forecast, technical measurement, functional acceptance, and authorized decision. If an off-roster developer performed a correction, record assisted recovery and the unresolved dependency. Define knowledge transfer, access, coverage, and a repeat rehearsal by the intended shift. This lesson’s forty-five-minute workshop uses synthetic data to produce a decision matrix and an English status message. Running the model validates calculations rather than human autonomy. Cases do not represent BNP Paribas procedures or establish regulatory conformance; independent specialist review remains pending alongside execution in an appropriately authorized operational environment.
OFICINA / WORKSHOP: 45 minutos / 45 minutes
Exercício de decisão com dados fictícios. Não executar mudanças reais.
Decision exercise using fictional data. Do not perform real changes.
0-10: Executar o código da aula anterior / Run the preceding lesson code:
python3 run.py --output evidence.json
Confirmar / Confirm: 32 checks; runtime; runnerSha256.
Identificar quais os números assumidos e quais os resultados calculados.
Identify assumed numbers and calculated outcomes.
10-20: Preparar uma matriz / Prepare a matrix:
Critério | Hipótese | Evidência observada | Lacuna | Responsável
Criterion | Assumption | Observed evidence | Gap | Owner
Incluir capacidade, paralelismo, dados, acesso e autonomia RUN.
Include capacity, parallelism, data, access, and RUN autonomy.
20-30: Injetar o cenário / Inject this scenario:
elapsed=85; window=150; return=35; validation=15; reserve=10
37 novas instruções depois do corte; reconciliação sem duração medida.
37 new instructions after cut; reconciliation has no measured duration.
Explicar o que impede garantir retorno dentro da janela.
Explain what prevents guaranteeing return inside the window.
30-40: Comparar A100/B200/C300 com A100/B250/D250.
Compare A100/B200/C300 with A100/B250/D250.
Registar missing=C, unexpected=D, changed=B.
Record missing=C, unexpected=D, changed=B.
Definir a evidência necessária antes de reabrir.
Define evidence required before reopening.
40-45: Escrever uma atualização em inglês / Write an English status update:
Observed outcome / unresolved integrity / remaining margin /
decision owner / next checkpoint.
Não confundir o modelo com um ensaio bancário executado.
Do not describe the model as an executed banking rehearsal.
At minute 85, a 150-minute window with 60 reserved for return leaves five minutes. New writes need reconciliation before return can be declared safe.
Common pitfalls
Stopping timing at database startup, accepting totals without references, restoring an old copy over new writes, or hiding project-team assistance.
Related topics: Services, dependencies, and evidence · Resilience and data recovery · Cloud, costs, and RUN autonomy
Reopening depends on usable service and consistent data; reserved time and new writes are part of the decision.
Reference: OPS07-BP05 Make informed decisions to deploy systems and changes · BigSavant banking infrastructure professional assessment2026.10