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ADR-010-v4: Disaster Recovery Architecture (Part 1: Narrative)

Document: ADR-010-v4-disaster-recovery-part1-narrative
Version: 1.0.1
Purpose: Define comprehensive disaster recovery strategy for human understanding
Audience: Business stakeholders, operations teams, security teams
Date Created: 2025-08-31
Date Modified: 2025-08-31
QA Reviewed: 2025-08-31
Status: DRAFT
Supersedes: None

Table of Contents​

1. Document Information 🔴 REQUIRED​

FieldValue
ADR NumberADR-010
TitleDisaster Recovery Architecture
StatusDraft
Date Created2025-08-31
Last Modified2025-08-31
Version1.0.0
Decision MakersCTO, Operations Lead, Security Officer
StakeholdersAll CODITECT teams, customers

2. Purpose of this ADR 🔴 REQUIRED​

This ADR serves dual purposes:

  • For Humans 👥: Understand how CODITECT protects against disasters and ensures business continuity
  • For AI Agents 🤖: Implement automated backup, replication, and recovery procedures

3. User Story Context 🔴 REQUIRED​

As a CODITECT platform customer,
I want my data and workspaces to survive any disaster,
So that my development work is never lost and always accessible.

As an operations engineer,
I want automated disaster recovery procedures,
So that I can restore service quickly with minimal manual intervention.

As a compliance officer,
I want documented recovery procedures and tested RTO/RPO,
So that we meet regulatory requirements and customer SLAs.

📋 Acceptance Criteria:​

  • RPO (Recovery Point Objective) ≤ 1 hour
  • RTO (Recovery Time Objective) ≤ 4 hours
  • Automated failover for critical services
  • Regular backup verification
  • Documented recovery procedures
  • Quarterly disaster recovery tests
  • Zero data loss for committed transactions

4. Executive Summary 🔴 REQUIRED​

🏢 For Business Stakeholders​

Imagine CODITECT as a bank vault for your code. Just as banks don't keep all money in one vault, we don't keep all data in one place. We maintain multiple synchronized copies across different geographic locations.

If disaster strikes—whether it's a data center fire, network outage, or regional catastrophe—your development work continues uninterrupted. Think of it like having multiple backup generators: when one fails, another automatically takes over.

Business Value:

  • 99.99% uptime guarantee
  • Maximum 1 hour of potential work loss
  • Service restored within 4 hours
  • Customer trust through proven resilience

Key Decision: Implement multi-region active-passive disaster recovery with automated failover.

💻 For Technical Readers​

Technical Summary: FoundationDB 3-region replication with automated failover, continuous backups to GCS, and orchestrated recovery procedures via Kubernetes operators.

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5. Visual Overview 🔴 REQUIRED​

5.1 Disaster Recovery Concept​

5.2 RTO/RPO Timeline​

5.3 Multi-Region Architecture​

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6. Background & Problem 🔴 REQUIRED​

6.1 Business Context​

Why this matters:

  • Customer Trust: Developers trust us with their code—we must never lose it
  • Business Continuity: Every hour of downtime costs customers productivity
  • Competitive Advantage: Superior reliability differentiates us from competitors
  • Regulatory Compliance: Many customers require documented DR procedures

User impact:

  • Lost work devastating for developers
  • Downtime blocks entire development teams
  • Data loss could mean weeks of rework
  • Service interruptions damage reputation

Cost of inaction:

  • Single major outage could lose 30% of customers
  • Regulatory fines for non-compliance
  • Litigation risk from data loss
  • Irreparable reputation damage

6.2 Technical Context​

Current state:

  • Single region deployment
  • Daily backups only
  • Manual recovery procedures
  • No automated failover
  • Limited monitoring

Limitations:

  • Regional outage = complete downtime
  • 24-hour potential data loss
  • 8-12 hour recovery time
  • No real-time replication
  • Untested procedures

Technical debt:

  • Backup scripts not automated
  • No backup verification
  • Recovery procedures outdated
  • Monitoring gaps
  • Single points of failure

6.3 Constraints​

TypeConstraintImpact
⏰ TimeMust implement within Q1Phased rollout required
💰 Budget$50K monthly DR budgetUse existing cloud credits
👥 ResourcesCurrent ops team onlyAutomation critical
🔧 TechnicalFoundationDB limitationsWork within FDB features
📜 ComplianceSOC 2 requirementsMust document everything

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7. Decision 🔴 REQUIRED​

7.1 Y-Statement Format​

In the context of protecting customer data and ensuring service availability,
facing single region deployment risks and compliance requirements,
we decided for multi-region active-passive DR with automated failover
and neglected active-active (too complex) and cold backup only (too slow),
to achieve RPO ≤ 1 hour, RTO ≤ 4 hours, and 99.99% availability,
accepting increased infrastructure costs and operational complexity,
because customer trust and business continuity outweigh the costs.

7.2 What We're Doing​

Implementing a comprehensive disaster recovery solution:

  1. Multi-Region Deployment

    • Primary region: us-central1
    • Standby region 1: us-east1
    • Standby region 2: europe-west1

  2. FoundationDB Replication

    • 3-datacenter configuration
    • Synchronous replication
    • Automatic failover capability

  3. Continuous Backups

    • Hourly snapshots to GCS
    • Cross-region backup replication
    • 30-day retention minimum

  4. Automated Recovery

    • Kubernetes operators for failover
    • DNS-based traffic switching
    • Health check automation

7.3 Why This Approach​

Multi-region provides:

  • Protection against regional disasters
  • Reduced latency for global users
  • Compliance with data residency
  • Foundation for future expansion

FoundationDB replication ensures:

  • Zero data loss for committed transactions
  • Sub-second replication lag
  • Automatic consistency guarantees
  • Built-in split-brain prevention

This approach balances:

  • Cost vs protection level
  • Complexity vs reliability
  • Automation vs control
  • Performance vs resilience

7.4 Alternatives Considered 🟡 OPTIONAL​

Option A: Active-Active Multi-Region​

AspectDetails
DescriptionAll regions serve traffic simultaneously
✅ Pros• Zero failover time
• Better global performance
• Load distribution
❌ Cons• Complex conflict resolution
• Higher costs
• Difficult troubleshooting
Rejection ReasonComplexity outweighs benefits for current scale

Option B: Cold Backup Only​

AspectDetails
DescriptionDaily backups with manual restoration
✅ Pros• Very low cost
• Simple implementation
• Minimal complexity
❌ Cons• 24-hour data loss risk
• 8+ hour recovery time
• Manual processes
Rejection ReasonDoesn't meet RTO/RPO requirements

Option C: Single Standby Region​

AspectDetails
DescriptionOne primary, one standby region only
✅ Pros• Lower cost than 3 regions
• Simpler than multi-standby
• Meets basic requirements
❌ Cons• No protection if both fail
• Can't serve global users well
• Limited expansion path
Rejection ReasonInsufficient protection and growth limitations

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8. Implementation Blueprint 🔴 REQUIRED​

8.1 Architecture Diagram​

8.2 Recovery Procedures​

Automatic Failover Process​

Manual Recovery Steps​

  1. Assess Situation (15 minutes)

    • Verify primary is truly down
    • Check data consistency
    • Review recent backups

  2. Initiate Failover (30 minutes)

    • Execute failover command
    • Verify standby promotion
    • Update configuration

  3. Validate Services (45 minutes)

    • Test all API endpoints
    • Verify data integrity
    • Check background jobs

  4. Resume Operations (15 minutes)

    • Update status page
    • Notify customers
    • Document incident

8.3 Backup Strategy​

Continuous Backups:

backup_policy:
  frequency: hourly
  retention:
    hourly: 24  # Keep 24 hourly backups
    daily: 30   # Keep 30 daily backups
    monthly: 12 # Keep 12 monthly backups
  
  locations:
    primary: gs://coditect-backups-us/
    secondary: gs://coditect-backups-eu/
  
  verification:
    automated_restore_test: daily
    full_restore_test: monthly

8.4 Configuration Management​

All disaster recovery configurations are managed through standardized YAML files stored in version control. See Part 2: Technical Implementation for complete configuration schemas.

8.5 Logging Requirements (Reference)​

All DR events must be logged using CODITECT's standard logging format. Critical events include:

  • Failover initiation and completion
  • Backup success/failure
  • Replication lag warnings
  • Health check status changes

Detailed logging patterns and implementations are provided in Part 2: Technical Implementation.

8.6 Error Handling Approach​

The DR system implements graceful error handling:

  • Automatic retry with exponential backoff
  • Circuit breakers to prevent cascade failures
  • User-friendly error messages during outages
  • Fallback procedures for automation failures

Complete error handling patterns with code examples are in Part 2: Technical Implementation.

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9. Testing Strategy 🔴 REQUIRED​

9.1 DR Testing Schedule​

Test TypeFrequencyDurationScope
Backup VerificationDaily30 minAutomated restore test
Failover SimulationMonthly2 hoursSingle service failover
Regional FailoverQuarterly4 hoursFull region failover
Disaster SimulationAnnually8 hoursComplete DR exercise

9.2 Test Scenarios​

  1. Network Partition

    • Simulate network split
    • Verify automatic handling
    • Measure recovery time

  2. Data Center Loss

    • Simulate complete DC failure
    • Execute failover procedures
    • Validate zero data loss

  3. Cascading Failures

    • Multiple component failures
    • Test escalation procedures
    • Verify graceful degradation

  4. Data Corruption

    • Simulate corrupted data
    • Test backup restoration
    • Verify point-in-time recovery

9.3 Test Coverage Requirements​

All disaster recovery components must meet these coverage targets:

Test TypeCoverage TargetMeasurement Tool
Unit Tests≥ 80%cargo tarpaulin
Integration Tests≥ 70%Custom metrics
End-to-End Tests≥ 60%Scenario coverage
Chaos Tests100% scenariosChaos engineering

Coverage includes:

  • All failover logic paths
  • Error handling branches
  • Configuration validation
  • Health check algorithms

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10. Security Considerations 🔴 REQUIRED​

10.1 Security During Disasters​

Access Control:

  • Emergency access procedures
  • Break-glass accounts ready
  • Audit trail maintained
  • MFA still enforced

Data Protection:

  • Backups encrypted at rest
  • Replication uses TLS
  • Keys stored in Cloud KMS
  • Regular security scans

10.2 Compliance Maintenance​

During Failover:

  • Audit logs preserved
  • Compliance controls active
  • Data residency maintained
  • Access controls enforced

Evidence Collection:

  • Automated screenshots
  • Configuration backups
  • Decision logging
  • Timeline documentation

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11. Performance Characteristics 🔴 REQUIRED​

11.1 DR Metrics​

MetricTargetCurrentMeasurement
RPO≤ 1 hourN/ATime since last backup
RTO≤ 4 hoursN/ATime to restore service
Failover Time≤ 15 minN/AAutomated switchover
Data Sync Lag< 1 secondN/AReplication latency
Backup Success99.9%N/ASuccessful/total

11.2 Performance Impact​

Normal Operation:

  • 5% overhead from replication
  • Negligible user impact
  • Background backup jobs
  • Async monitoring

During Failover:

  • 15-minute service interruption
  • No data loss
  • Full performance after failover
  • Automatic client reconnection

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12. Operational Considerations 🔴 REQUIRED​

12.1 Runbook Structure​

Pre-Disaster:

  • Health monitoring dashboards
  • Automated backup verification
  • Regular DR drills
  • Documentation updates

During Disaster:

  • Incident command structure
  • Communication protocols
  • Decision trees
  • Escalation procedures

Post-Disaster:

  • Service restoration
  • Root cause analysis
  • Lessons learned
  • Process improvements

12.2 Monitoring & Alerts​

AlertThresholdAction
Replication Lag> 5 secondsInvestigate immediately
Backup FailureAny failureRetry and escalate
Region Health< 95% healthyPrepare for failover
Storage Usage> 80% fullExpand capacity

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13. Migration Strategy 🔴 REQUIRED​

13.1 Implementation Phases​

Phase 1: Foundation (Month 1)

  • Deploy standby regions
  • Configure FDB replication
  • Set up backup automation
  • Create monitoring dashboards

Phase 2: Automation (Month 2)

  • Implement failover controller
  • Create recovery runbooks
  • Deploy health monitors
  • Test backup restoration

Phase 3: Validation (Month 3)

  • Conduct failover tests
  • Train operations team
  • Update documentation
  • Customer communication

13.2 Rollback Plan​

If issues arise:

  1. Revert to single region
  2. Maintain current backups
  3. Fix identified issues
  4. Retry implementation

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14. Consequences 🔴 REQUIRED​

14.1 Positive Outcomes​

✅ Business Benefits:

  • 99.99% availability SLA possible
  • Customer confidence increased
  • Compliance requirements met
  • Competitive advantage gained

✅ Technical Benefits:

  • Automated recovery procedures
  • Improved monitoring
  • Better testing practices
  • Reduced manual work

✅ Risk Reduction:

  • Regional disasters survivable
  • Data loss near-impossible
  • Faster incident resolution
  • Proven recovery procedures

14.2 Negative Impacts​

⚠️ Increased Costs:

  • 3x infrastructure for regions
  • Additional storage for backups
  • Higher bandwidth usage
  • More complex billing

⚠️ Operational Complexity:

  • More systems to monitor
  • Complex troubleshooting
  • Training requirements
  • Documentation overhead

⚠️ Technical Challenges:

  • Network latency between regions
  • Complex failure scenarios
  • Testing disruptions
  • Upgrade coordination

14.3 Risk Register​

RiskProbabilityImpactMitigationOwner
Split-brain scenarioLowCriticalFDB prevents thisOps
Cascade failuresMediumHighCircuit breakersDev
Human error in failoverMediumHighAutomationOps
Backup corruptionLowCriticalMultiple copiesOps

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15. References & Standards 🔴 REQUIRED​

15.2 External Documentation​

15.3 Standards & Compliance​

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16. Review & Approval 🔴 REQUIRED​

Approval Signatures​

RoleNameDateSignature
CTO_________________________
Operations Lead_________________________
Security Officer_________________________
CFO_________________________

Review History​

VersionDateReviewerStatusComments
0.12025-08-31SESSION4DRAFTInitial draft created
1.0.12025-08-31SESSION4DRAFTFixed v4.2 compliance issues

Approval Workflow​

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Next: See Part 2: Technical Implementation for detailed technical specifications.

17. Appendix​

17.1 Glossary​

TermDefinition
RPORecovery Point Objective - Maximum acceptable data loss measured in time
RTORecovery Time Objective - Maximum acceptable downtime
DRDisaster Recovery - Process of restoring services after catastrophic failure
FailoverProcess of switching from primary to standby systems
FDBFoundationDB - The distributed database used by CODITECT
GCSGoogle Cloud Storage - Object storage for backups
Split-brainSituation where two systems think they are primary
Active-PassiveDR model where standby systems wait idle until needed
Replication LagDelay between primary write and standby update
Break-glassEmergency access procedure bypassing normal controls

17.2 Stakeholder Impact Analysis​

StakeholderNormal OperationsDuring DisasterPost-Recovery
CustomersFull service accessBrief interruption (≤4hr)Normal service resumed
DevelopersStandard workflowsRead-only mode possibleFull access restored
OperationsRoutine monitoringIncident response modeRCA and improvements
SecurityStandard controlsEmergency proceduresAudit and review
ComplianceRegular auditsEvidence collectionReport generation
FinanceNormal costsIncreased cloud usageCost reconciliation

17.3 Version Control Strategy​

This document follows semantic versioning:

  • Major (X.0.0): Fundamental DR strategy changes
  • Minor (1.X.0): New features or significant updates
  • Patch (1.0.X): Corrections and clarifications

All versions are tracked in Git with tagged releases.

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18. QA Review Block​

Status: AWAITING INDEPENDENT QA REVIEW

This section will be completed by an independent QA reviewer (not the author) according to ADR-QA-REVIEW-GUIDE-v4.2.

Document ready for review as of: 2025-08-31
Version ready for review: 1.0.1