Disasters happen. Hardware fails, ransomware attacks, human errors, and natural disasters can all take down your infrastructure. The difference between a minor inconvenience and a catastrophic business failure is the quality of your disaster recovery (DR) plan.
Key DR Metrics
- RTO (Recovery Time Objective): Maximum acceptable downtime. How long can your business survive without this system?
- RPO (Recovery Point Objective): Maximum acceptable data loss. How much data can you afford to lose?
- MTTR (Mean Time to Recovery): Average time to restore service after a failure.
Risk Assessment
Identify and categorize potential threats:
- Hardware failures: Disk crashes, power supply failures, memory errors
- Software failures: Corrupted databases, failed updates, application bugs
- Human errors: Accidental deletion, misconfiguration, unauthorized changes
- Cyber attacks: Ransomware, data breaches, DDoS attacks
- Natural disasters: Fire, flood, earthquake, power outages
- Vendor failures: Cloud provider outages, DNS failures
The 3-2-1-1-0 Backup Rule
An evolution of the classic 3-2-1 rule:
- 3 copies of your data
- 2 different storage media types
- 1 offsite copy
- 1 immutable or air-gapped copy (ransomware protection)
- 0 errors in backup verification tests
DR Plan Components
1. System Inventory
Document every system, its priority level, and dependencies:
- Critical systems (RTO: minutes): Payment processing, authentication, primary database
- Important systems (RTO: hours): Email, monitoring, internal tools
- Standard systems (RTO: days): Development environments, archives, documentation
2. Backup Procedures
# Example automated backup script
#!/bin/bash
TIMESTAMP=$(date +%Y%m%d_%H%M%S)
BACKUP_DIR="/backup/$TIMESTAMP"
# Database backup
pg_dump -h localhost -U admin production_db | gzip > "$BACKUP_DIR/db.sql.gz"
# File system backup
borg create --stats --compression zstd \
/backup/borg-repo::auto-$TIMESTAMP \
/var/www /etc /home
# Verify backup integrity
borg check /backup/borg-repo
# Sync to offsite storage
rclone sync /backup/borg-repo remote:backups/borg-repo --transfers 4
# Log result
echo "$TIMESTAMP - Backup completed successfully" >> /var/log/backup.log3. Recovery Procedures
Document step-by-step recovery for each critical system:
- Assess the scope and nature of the failure
- Notify the incident response team
- Follow the system-specific recovery runbook
- Verify data integrity after restoration
- Test functionality before declaring recovery complete
- Document the incident and lessons learned
4. Communication Plan
- Who needs to be notified and in what order
- Internal communication channels (backup channels if primary is down)
- External communication: customers, partners, regulators
- Status page updates
Testing Your DR Plan
- Tabletop exercise: Walk through scenarios verbally (quarterly)
- Partial test: Restore individual systems to verify backups (monthly)
- Full simulation: Complete DR drill with failover (annually)
- Chaos engineering: Deliberately introduce failures to test resilience
Documentation Checklist
- System inventory with criticality levels
- Contact list with escalation procedures
- Step-by-step recovery runbooks for each system
- Network diagrams and access credentials (stored securely)
- Vendor contact information and support procedures
- Post-incident review template
A disaster recovery plan is like insurance — you hope you never need it, but when you do, it is invaluable. Invest the time to create, document, and regularly test your DR procedures. Your future self will thank you.
