AWS Database High Availability Options

Operational Efficiency Spectrum

High Operational Efficiency (Less Control)

• AWS manages elasticity and HA

• Limited control over engine/architecture

• Automated management

• Simplified operations

Low Operational Efficiency (Maximum Control)

• Complete control over all aspects

• Manual OS updates and patches

• Custom configuration options

• Higher maintenance overhead

Database Options Overview

DynamoDB

Characteristics

• Highest operational efficiency

• NoSQL-only solution

• Built-in high availability

• Default regional distribution

High Availability Features

• Data distribution across partitions

• Three-AZ spread per region

• Global tables support

• Automatic failover handling

Amazon Aurora

Characteristics

• Best HA option for relational data

• Minimal operational overhead

• Multi-AZ/Multi-region capable

• Read replica support

High Availability Features

• Synchronous data replication

• Cross-AZ distribution

• Global database option

• Automatic failover

• Up to five secondary regions

Implementation Details

• Main instance with multiple read replicas

• Cross-AZ data copies

• Automatic promotion of read replicas

• Storage-level replication for global databases

Amazon RDS

Characteristics

• Good HA capabilities

• More complex multi-region setup

• Standby instances don't serve traffic

• Synchronous replication

High Availability Options

1. Multi-AZ Deployment

   • Synchronous replication

   • Automatic failover

   • Standby instances for failover only

2. Regional Read Replicas

   • Warm standby option

   • Manual promotion required

   • Cross-region capability

1. Backup and Recovery

   • S3 snapshot storage

   • Higher RTO tolerance

   • Potential data loss depending on frequency

Amazon Redshift

Current HA Options

• Multi-node clusters (primary method)

• RA3 instances (preview) for multi-AZ

• S3 snapshot restoration for single-node

RA3 Instance Features

• Redshift Managed Storage (RMS)

• S3-based storage layer

• Cross-AZ compute provisioning

• Automatic failover capability

Implementation Considerations

DynamoDB Implementation

• Enable global tables for multi-region

• Configure read/write capacity

• Monitor partition distribution

• Plan capacity requirements

Aurora Implementation

• Deploy across multiple AZs

• Configure read replicas

• Enable global databases if needed

• Set up automatic failover

RDS Implementation

• Choose appropriate HA strategy

• Configure backup schedules

• Plan for regional redundancy

• Set up monitoring and alerts

Redshift Implementation

• Select appropriate instance type

• Configure multi-node clusters

• Plan backup strategy

• Monitor cluster health

Best Practices

Selection Criteria

1. Data Type Requirements

   • NoSQL: Consider DynamoDB

   • Relational: Aurora or RDS

   • Data Warehouse: Redshift

2. Availability Requirements

   • Regional vs Global

   • RTO/RPO requirements

   • Failover needs

3. Operational Considerations

   • Management overhead

   • Cost implications

   • Maintenance requirements

Monitoring and Maintenance

• Regular health checks

• Performance monitoring

• Backup verification

• Failover testing

Exam Considerations

• DynamoDB is optimized for HA in NoSQL scenarios

• Aurora provides best relational database HA features

• RDS offers multiple HA options with different trade-offs

• Redshift achieves HA primarily through multi-node clusters

• Consider operational efficiency vs control requirements