#disaster-recovery

Design load balancing and high availability systems for fault-tolerant, scalable application infrastructure. Load balancing strategies: 1. Application Load Balancer (ALB): Layer 7 routing, host/path-based routing, SSL termination. 2. Network Load Balancer (NLB): Layer 4 performance, static IP addresses, ultra-low latency. 3. Global load balancing: geographical distribution, DNS-based routing, CDN integration. Health checks: 1. HTTP health endpoints: /health returning 200 OK, comprehensive system status checks. 2. Check intervals: 30-second intervals, 3 consecutive failures for unhealthy marking. 3. Custom metrics: database connectivity, external service dependencies, resource availability. High availability design: 1. Multi-AZ deployment: minimum 2 availability zones, automatic failover mechanisms. 2. Auto Scaling Groups: CPU target 70%, predictive scaling for traffic patterns. 3. Circuit breaker pattern: fail fast when dependencies unavailable, graceful degradation. Performance optimization: 1. Connection pooling: database connections, HTTP keep-alive, connection limits. 2. Caching strategies: Redis/ElastiCache, CDN caching, application-level caching. 3. Content delivery: static assets via CDN, edge locations, cache invalidation strategies. Disaster recovery: 1. Cross-region replication: RTO < 4 hours, RPO < 1 hour for critical systems. 2. Backup strategies: automated daily backups, point-in-time recovery, cross-region backup storage. Traffic management: blue-green deployments, canary releases with 5% traffic initially, feature flags for instant rollback.

Develop business continuity plan. Components: 1. Risk assessment (identify threats). 2. Business impact analysis. 3. Critical business functions prioritization. 4. Recovery strategies for each function. 5. Emergency response procedures. 6. Communication plan. 7. Backup systems and data. 8. Regular testing and updates. Include DR for IT systems. Define RPO and RTO. Document contact information. Train team. Hope for best, plan for worst.

Design a comprehensive database backup strategy. Components: 1. Automated daily full backups. 2. Incremental backups every 6 hours. 3. Point-in-time recovery capability. 4. Offsite backup storage (S3 Glacier). 5. Encryption at rest and in transit. 6. Backup verification and integrity checks. 7. Documented restore procedures with RTO/RPO. Test restore process monthly. Use tools like pg_dump, mysqldump, or cloud-native solutions. Include retention policies (7 daily, 4 weekly, 12 monthly).

Implement comprehensive backup and disaster recovery automation for business continuity and data protection. Backup strategies: 1. 3-2-1 rule: 3 copies of data, 2 different media types, 1 offsite location. 2. Recovery objectives: RTO (Recovery Time Objective) <4 hours, RPO (Recovery Point Objective) <1 hour. 3. Backup types: full (weekly), incremental (daily), differential options based on data change rate. Automated backup systems: 1. Database backups: automated SQL dumps, point-in-time recovery, transaction log backups. 2. File system backups: rsync, duplicity for encrypted backups, snapshot-based backups. 3. Application data: configuration backups, state snapshots, user data preservation. Cloud backup solutions: 1. AWS Backup: cross-service backup management, automated backup policies, compliance reporting. 2. Azure Backup: VM backups, SQL Server backup, file/folder level recovery. 3. Google Cloud Backup: automated VM snapshots, database backup scheduling. Disaster recovery planning: 1. Failover automation: DNS switching, load balancer reconfiguration, database promotion. 2. Recovery testing: monthly DR drills, automated failover testing, recovery time validation. 3. Documentation: runbooks, contact lists, escalation procedures, vendor contacts. Data validation: 1. Backup verification: restore testing, data integrity checks, backup completion monitoring. 2. Compliance: retention policies (7 years for financial data), encryption requirements. Monitoring and alerting: backup success/failure notifications, storage capacity monitoring, restore time tracking, compliance dashboard with audit trails.

Design and implement multi-cloud architecture for vendor independence, geographic distribution, and improved reliability. Multi-cloud benefits: 1. Vendor independence: avoid lock-in, negotiate better pricing, access best-of-breed services. 2. Geographic coverage: global presence, data sovereignty compliance, disaster recovery across regions. 3. Cost optimization: spot instances, reserved capacity across providers, workload placement. Architecture patterns: 1. Active-active: traffic distribution across clouds, data synchronization, consistent user experience. 2. Active-passive: primary cloud with failover capability, automated disaster recovery. 3. Hybrid: on-premises integration, cloud bursting for peak loads, gradual migration strategies. Cloud-agnostic tooling: 1. Terraform: multi-provider infrastructure as code, consistent deployment patterns. 2. Kubernetes: container orchestration across clouds, workload portability, unified management. 3. Service mesh: cross-cloud networking, security policies, traffic management. Data management: 1. Data replication: real-time sync, conflict resolution, consistency models (eventual consistency). 2. Database strategies: read replicas across regions, sharding, multi-master configurations. 3. Backup strategies: cross-cloud backup storage, geo-redundancy, compliance requirements. Networking: 1. VPN connectivity: site-to-site VPN, dedicated connections (AWS Direct Connect, Azure ExpressRoute). 2. Load balancing: global DNS-based routing, health checks, failover automation. Monitoring: unified observability across clouds, cost tracking, performance comparison, vendor-specific metrics normalization for consistent reporting and alerting.