A decision folder is not finished until someone attacks it. Management asks why two regions are needed. Security asks why operations should maintain the firewall. Sales asks why the reports do not run on the main database. This lesson shows how to answer such questions without repeating the decision, and how to review the folder with a questionnaire. At the end, it looks at where you can keep learning in the academy and at Microsoft.
Prior knowledge. You know the folder and its contradictions from lesson 7.1, the ADR form from lesson 0.1, and the five pillars from the same lesson. How an architecture review works in a team and how to defend a decision in front of a committee are taught in "K4, lesson 4.14.6" and "K4, lesson 4.14.7," and how to record it as an ADR in "K4, lesson 4.1.3." None of that is repeated here. What is new is the defense from the requirements sheet: every answer points to a row, not to taste.
Trade-offs between the pillars
Every decision in the folder improves one pillar and costs another. For each pillar, Microsoft has a page of its own on trade-offs; the links are under "Further reading." Nordlicht Reisen shows the patterns you will meet again in the exam and on the job:
| Decision in the folder | Pillar it serves | Pillar that pays | How the folder holds it |
|---|---|---|---|
| second region with failover group and Front Door | Reliability | Cost Optimization | M-02 is a Must, M-10 a Could: the commitment wins |
| private endpoint, no public access | Security | Operational Excellence | DNS and rules need maintenance; M-04 is a Must |
| manual switchover of the failover group | Operational Excellence, security of the data | Reliability | the decision time of a human counts toward the RTO |
| zone redundancy in the App Service plan | Reliability | Cost Optimization | the minimum number of instances rises, there is no separate surcharge |
| Hyperscale with a named replica | Performance Efficiency | Cost Optimization | the replicas are billed by time; in return, the reports do not run on the primary |
| Azure Firewall Standard in the hub | Security | Cost Optimization, Performance Efficiency | M-04 demands control of outbound traffic |
| Bicep and a deployment stack | Operational Excellence | Operational Excellence (effort to get started) | M-09 demands repeatability |
The column "How the folder holds it" is the real content. A trade-off is decided only when a row of the requirements sheet supports it. That is the order of priority from lesson 0.2: law and contract, then booking at the load peak, then cost, then convenience. Anyone who forgets it defends a design with the sentence "that is best practice," and that holds against no objection.