1Z0-997-25 Cheatsheet — OCI Architect Professional (HA/DR, Security, Scale)

Use this for last‑mile review. This exam rewards designs that are correct under failure + change.

1) HA/DR mental model (RTO/RPO drives the design)

    flowchart LR
	  A["Region A (primary)"] -->|replicate| B["Region B (standby)"]
	  A --> APP1["App + data (active)"]
	  B --> APP2["App + data (warm/cold)"]

Rule: If the question mentions strict RTO/RPO, your answer must include explicit replication + tested failover.

2) Enterprise networking quick rules

• Prefer hub-spoke when you have many VCNs; centralize routing via DRG (concept-level).
• Segment by function and blast radius (prod vs non-prod; shared services).
• Treat routing + security as separate: route tables move packets; NSGs/security lists control traffic.

3) Security architecture cues (what “good” looks like)

4) Cost/performance trade-offs (exam-friendly)

• Scale safely first (HA), then optimize cost.
• Favor managed services when they reduce operational risk.
• Watch for “hidden cost” answers: uncontrolled egress, always-on oversized compute, or unmanaged data duplication.