sethdford Disaster Recovery Plan
Design recovery strategies with defined objectives, tested procedures, and regular validation.
Context
You are planning disaster recovery. Define RTO/RPO requirements, design backup and failover strategies, plan testing. Read business impact analysis, current backups, and regulatory requirements.
Domain Context
Based on IT disaster recovery best practices (NIST, ISO 27031):
- RTO (Recovery Time Objective): How long can system be down? 1 hour? 1 day? Determines failover strategy.
- RPO (Recovery Point Objective): How much data loss acceptable? 1 hour? 1 day? Determines backup frequency.
- Backup Strategies: Full (complete copy), incremental (only changes since last backup), continuous replication
- Failover: Automatic (heartbeat-driven) vs manual (operations-triggered). Planned vs unplanned.
- Testing: Regular drills validate procedures; practice before disaster strikes
Instructions
Define Business Requirements: For each critical system, what's RTO (max downtime) and RPO (max data loss)? Business impact: lost revenue, SLA violations, customer trust?
Design Backup Strategy: Full daily backup + hourly incremental. Or continuous replication for stricter RPO. Test recovery from backups monthly; document recovery steps.
Plan Failover: For RTO < 1 hour, set up active-passive (standby system). For RTO < 5 minutes, active-active (both systems live). Implement health checks and automatic failover.
Document Procedures: Who decides to failover? What are manual steps? How do you know failover succeeded? Test documentation with dry runs; update after each test.
Schedule Regular Testing: Monthly failover drills for critical systems. Test both planned (maintenance window) and unplanned (kill production server) scenarios. Document findings and improvements.
Anti-Patterns
- RTO/RPO Undefined: Assume everything needs sub-minute RTO. Result: over-engineering cost. Guard: Quantify business impact; set RTO/RPO accordingly per system.
- Backups Never Tested: Assume they work. Result: discover failures during actual disaster. Guard: Regular restore drills; track recovery metrics.
- Manual Failover for Low RTO: Plan manual process for 5-minute RTO. Result: missed SLA. Guard: Automate failover if RTO tight; test automation regularly.
- Ignoring Data Consistency in Failover: Assume data identical between systems. Result: data loss or corruption. Guard: Validate data integrity post-failover; have reconciliation procedure.
Further Reading
- Site Reliability Engineering by Google — production disaster recovery practices
- Disaster Recovery Planning by Salvatore D. Ficara — comprehensive DR framework
- Resilience Engineering by Erik Hollnagel — thinking about recovery and resilience