Disaster recovery is not a product you buy — it's a set of decisions about how much downtime and data loss the business can tolerate, translated into architecture. OCI gives you good building blocks for cross-region DR; the craft is in choosing the right pattern per workload and, above all, in rehearsing the failover until it's boring.
Start with RTO and RPO, not technology
- RTO (Recovery Time Objective) — how long the service may be down before recovery completes.
- RPO (Recovery Point Objective) — how much data, measured in time, you can afford to lose.
These two numbers, agreed per application with the business, determine everything else. A reporting system with RTO 24h / RPO 24h can live on nightly backups; an identity platform with RTO 1h needs warm standby infrastructure that's already running. Classify your estate into tiers first — critical, important, standard — and design one pattern per tier rather than one per application.
The four classic DR patterns
| Pattern | Typical RTO | Cost | Idea |
|---|---|---|---|
| Backup & restore | Hours–days | $ | Replicated backups; rebuild on demand |
| Pilot light | Hours | $$ | Data replicates continuously; compute created at failover |
| Warm standby | Minutes–hour | $$$ | Scaled-down copy always running in DR |
| Active/active | Near zero | $$$$ | Both regions serve traffic continuously |
OCI's building blocks for each layer
Data replication
- Block volumes — cross-region replication of volumes and volume groups; at failover you activate the replica and attach it to new or standby compute.
- Object Storage — bucket-level cross-region replication for backups, exports, and artefacts.
- Databases — Data Guard for Oracle Database; for OCI Database with PostgreSQL and other engines, use the platform's read replicas or scheduled backup copies depending on your RPO.
- Application-level replication — some platforms replicate themselves best: Active Directory replicates natively to DR domain controllers, and an Exchange DAG can stretch database copies across regions. Where an application has its own replication, prefer it over infrastructure-level copying.
Network foundations
Build the DR region as a mirror landing zone: same VCN structure with non-overlapping CIDRs, connected via Remote Peering over DRGs so replication traffic stays on Oracle's backbone. Keep firewall rules and routing symmetric — a failover that works at the compute layer but dies on a missing security rule is a depressingly common rehearsal finding.
Orchestration: Full Stack Disaster Recovery
OCI Full Stack DR (FSDR) is the region-to-region orchestrator: you group resources into DR Protection Groups, define DR Plans (switchover for planned moves, failover for disasters), and FSDR executes the steps — activating volume replicas, launching compute, running your custom scripts — as one auditable runbook. Its built-in prechecks and plan execution logs are half the value: they turn "we think DR works" into evidence.
Traffic steering
Users reach the surviving region through DNS. OCI's Traffic Management steering policies (failover type) health-check the primary endpoint and answer with the DR endpoint when it fails. For internal namespaces, plan the DNS cutover explicitly — a scripted, phased update of internal records is a legitimate and testable approach. Keep TTLs low (60–300s) on anything that participates in failover.
The runbook is the product
Every DR programme eventually learns the same lesson: the technology is the easy half. What makes recovery real is a written, ordered runbook per tier — dependencies first (network, DNS, identity), then data platforms, then applications — with named owners, verification steps, and a failback plan. Then rehearse:
- Tabletop — walk the runbook on paper quarterly.
- Component tests — restore a database, activate a volume replica, flip one DNS record.
- Full switchover — at least annually, run production from the DR region for a defined window, then fail back.
An untested DR plan is a hypothesis. A rehearsed one is a capability.
Closing thought
Cross-region DR on OCI is very achievable with native services: replication for data, mirror landing zones for infrastructure, FSDR for orchestration, and DNS steering for users. Spend your effort where it compounds — tiering the estate honestly, automating the runbook, and rehearsing until a failover is a procedure, not an adventure.
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