Disaster Recovery Guide

This guide covers disaster recovery (DR) planning, implementation, and testing to ensure business continuity in the event of major system failures or disasters.

Disaster Recovery Basics

Core Concepts

1. Recovery Objectives

   • Recovery Time Objective (RTO)
   • Recovery Point Objective (RPO)
   • Service Level Objectives (SLO)
   • Business Impact Analysis (BIA)

2. Recovery Strategies

   • Hot Standby
   • Warm Standby
   • Cold Standby
   • Pilot Light

3. Data Protection

   • Backup Strategies
   • Replication Methods
   • Data Validation
   • Retention Policies

DR Setup

Basic Configuration

# Initialize DR environment
./dr-setup.sh --init \
  --primary-dc dc1 \
  --dr-dc dc2 \
  --services "web,db,cache" \
  --rto "4h" \
  --rpo "15m"

# Configure replication
./dr-setup.sh --replication \
  --type synchronous \
  --verify-data \
  --monitor-lag

Advanced Configuration

# Configure advanced DR features
./dr-setup.sh --advanced \
  --auto-failover \
  --geo-routing \
  --data-validation \
  --automated-testing

# Set up monitoring
./dr-setup.sh --monitoring \
  --metrics all \
  --alerts enabled \
  --notification-channels "slack,email,pager"

Configuration Files

Basic DR Configuration

# /etc/lambdasoftworks/dr/config.yml
disaster_recovery:
  name: "production-dr"
  strategy: "hot-standby"
  
  datacenters:
    primary:
      name: "dc1"
      location: "us-east"
      services:
        - name: "web"
          replicas: 3
          priority: 1
        - name: "db"
          replicas: 2
          priority: 1
        - name: "cache"
          replicas: 3
          priority: 2
          
    secondary:
      name: "dc2"
      location: "us-west"
      services:
        - name: "web"
          replicas: 2
          priority: 1
        - name: "db"
          replicas: 2
          priority: 1
        - name: "cache"
          replicas: 2
          priority: 2
  
  replication:
    mode: "synchronous"
    verify: true
    max_lag: "5m"
    
  failover:
    automatic: true
    threshold: "5m"
    require_confirmation: true
    
  testing:
    schedule: "0 2 * * 0"  # Weekly
    duration: "2h"
    notification: true

Advanced DR Configuration

# /etc/lambdasoftworks/dr/advanced-config.yml
disaster_recovery:
  name: "enterprise-dr"
  
  strategies:
    web:
      type: "hot-standby"
      rto: "5m"
      rpo: "0"
      
    database:
      type: "hot-standby"
      rto: "5m"
      rpo: "0"
      
    storage:
      type: "warm-standby"
      rto: "1h"
      rpo: "15m"
      
    batch:
      type: "cold-standby"
      rto: "4h"
      rpo: "1h"
  
  datacenters:
    primary:
      name: "dc1"
      provider: "aws"
      region: "us-east-1"
      zones: ["us-east-1a", "us-east-1b"]
      
      networking:
        vpc: "vpc-12345"
        subnets:
          - "subnet-1"
          - "subnet-2"
        security_groups:
          - "sg-web"
          - "sg-db"
          
      resources:
        compute:
          instance_types:
            - "t3.large"
            - "m5.xlarge"
        storage:
          types:
            - "gp3"
            - "io2"
            
    secondary:
      name: "dc2"
      provider: "aws"
      region: "us-west-2"
      zones: ["us-west-2a", "us-west-2b"]
      
      networking:
        vpc: "vpc-67890"
        subnets:
          - "subnet-3"
          - "subnet-4"
        security_groups:
          - "sg-web-dr"
          - "sg-db-dr"
          
      resources:
        compute:
          instance_types:
            - "t3.large"
            - "m5.xlarge"
        storage:
          types:
            - "gp3"
            - "io2"
  
  data_management:
    replication:
      database:
        type: "synchronous"
        technology: "postgresql"
        verify_commits: true
        max_lag: "1s"
        
      storage:
        type: "asynchronous"
        technology: "s3"
        sync_interval: "15m"
        verify_checksums: true
        
    backup:
      full:
        schedule: "0 0 * * 0"
        retention: "30d"
      incremental:
        schedule: "0 */6 * * *"
        retention: "7d"
      
    archival:
      type: "glacier"
      schedule: "0 0 1 * *"
      retention: "7y"
  
  monitoring:
    metrics:
      collection_interval: "10s"
      retention: "90d"
      
    health_checks:
      interval: "30s"
      timeout: "5s"
      unhealthy_threshold: 3
      
    alerts:
      channels:
        - type: "pagerduty"
          service_key: "key123"
          severity_mapping:
            critical: "P1"
            warning: "P2"
            
        - type: "slack"
          webhook: "https://hooks.slack.com/..."
          channels:
            - "#dr-alerts"
            - "#ops"
            
    dashboards:
      - name: "DR Status"
        refresh: "30s"
        panels:
          - title: "Replication Lag"
            type: "gauge"
          - title: "Service Health"
            type: "status"
          - title: "Failover History"
            type: "timeline"
  
  testing:
    automated:
      schedule: "0 2 * * 0"
      duration: "2h"
      services:
        - name: "web"
          tests:
            - type: "failover"
            - type: "performance"
        - name: "database"
          tests:
            - type: "replication"
            - type: "consistency"
            
    manual:
      frequency: "quarterly"
      duration: "8h"
      procedures:
        - name: "Full DC Failover"
          steps:
            - "Verify replication status"
            - "Initiate failover"
            - "Verify service health"
            - "Run integration tests"

Recovery Procedures

Automated Recovery

# Initiate automated failover
./dr-manage.sh --failover \
  --to-dc dc2 \
  --services all \
  --verify \
  --auto-revert 4h

# Monitor recovery progress
./dr-manage.sh --monitor-recovery \
  --failover-id recovery_123 \
  --metrics all

Manual Recovery

# Manual failover procedure
./dr-manage.sh --manual-failover \
  --to-dc dc2 \
  --step-by-step \
  --confirmation-required

# Verify recovery
./dr-manage.sh --verify-recovery \
  --services all \
  --run-tests

Testing and Validation

Automated Testing

# Run DR test
./dr-test.sh --run \
  --scenario full-failover \
  --duration 2h \
  --notify-stakeholders

# Validate DR setup
./dr-test.sh --validate \
  --components all \
  --generate-report

DR Drills

# Prepare DR drill
./dr-test.sh --prepare-drill \
  --scenario dc-failure \
  --duration 4h \
  --team ops

# Execute DR drill
./dr-test.sh --execute-drill \
  --drill-id drill_123 \
  --record-actions

Monitoring and Alerts

Setup Monitoring

# Configure DR monitoring
./dr-monitor.sh --setup \
  --metrics all \
  --interval 30s \
  --retention 90d

# Configure alerts
./dr-monitor.sh --alerts \
  --rules-file dr-alerts.yml \
  --notification-channels all

Example Alert Rules

# /etc/lambdasoftworks/dr/alerts.yml
rules:
  - name: "Replication Lag Critical"
    condition: "replication_lag > 300"
    severity: "critical"
    channels: ["pagerduty", "slack"]
    
  - name: "DR Site Unhealthy"
    condition: "dr_health_score < 80"
    severity: "warning"
    channels: ["email", "slack"]
    
  - name: "Backup Failure"
    condition: "backup_status == 'failed'"
    severity: "critical"
    channels: ["pagerduty"]

Best Practices

Planning

1. Documentation

   • Maintain current procedures
   • Document dependencies
   • Keep contact information updated
   • Regular review and updates

2. Testing

   • Regular DR testing
   • Realistic scenarios
   • Documented results
   • Improvement tracking

3. Training

   • Staff training
   • Role assignments
   • Communication procedures
   • Escalation paths

Implementation

1. Infrastructure

   • Geographic distribution
   • Network redundancy
   • Resource isolation
   • Security controls

2. Data Management

   • Regular backups
   • Data validation
   • Secure transmission
   • Retention compliance

3. Automation

   • Automated procedures
   • Validation checks
   • Rollback capabilities
   • Monitoring integration

Troubleshooting

Common Issues

1. Replication Problems

# Check replication status
./dr-manage.sh --check-replication \
  --services all \
  --verbose

# Fix replication
./dr-manage.sh --fix-replication \
  --service db \
  --auto-recover

2. Failover Issues

# Diagnose failover
./dr-manage.sh --diagnose-failover \
  --failover-id recovery_123 \
  --detailed-logs

# Reset failover
./dr-manage.sh --reset-failover \
  --failover-id recovery_123 \
  --force

Next Steps

• Backup Strategies
• Security Hardening
• Compliance Guide
• Crisis Management