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Difficulty: Very hardDatabase and Storage Strategy

A media streaming company is designing a globally distributed user profiling and watch-history platform. The database must sustain high-volume OLTP write operations with sub-10 millisecond latency. The platform must be deployed across two AWS Regions (us-east-1 and us-west-2). A centralized security account (SecurityAcct) requires cross-account read access to audit the database encryption keys and metadata. The system must achieve a Recovery Point Objective (RPO) of less than 1 second and a Recovery Time Objective (RTO) of less than 5 minutes. Additionally, read workloads are highly dynamic and experience sudden, unpredictable surges. Which database and storage design meets these requirements while minimizing management overhead?

  1. A
    Deploy Amazon RDS for PostgreSQL in a Multi-AZ deployment across us-east-1 and us-west-2. Configure the application to route read traffic to the standby instance in the secondary Availability Zone during peak load to scale query performance. Configure cross-region read replicas to achieve low-latency cross-region replication.
  2. Deploy Amazon DynamoDB Global Tables across us-east-1 and us-west-2. Configure DynamoDB Auto Scaling for both read and write capacity units to handle dynamic surges. Use a Customer Managed Key (CMK) in AWS KMS in each region, and update the key policies to grant decryption and metadata permissions to the audit role in the centralized security account.Answer
  3. C
    Deploy a single-region Amazon DynamoDB table in us-east-1. Configure AWS Backup to copy table backups hourly to us-west-2. In the event of a disaster in us-east-1, restore the table from the backup in us-west-2 and update DNS records to point to the new regional endpoint.
  4. D
    Deploy Amazon DynamoDB Global Tables across us-east-1 and us-west-2. Configure DynamoDB Auto Scaling for both read and write capacity units. Secure the tables using the default AWS managed KMS key (aws/dynamodb) in each region, and attach a key-sharing policy to allow the audit role in the centralized security account to access the key.

Answer

Deploy Amazon DynamoDB Global Tables across us-east-1 and us-west-2, using DynamoDB Auto Scaling and Customer Managed Keys (CMKs) with key policies updated to delegate cross-account access to the centralized security account.
The correct answer configuration utilizes Amazon DynamoDB Global Tables, which provides fully managed active-active replication across multiple regions with sub-second RPO and extremely low RTO. DynamoDB Auto Scaling automatically adjusts capacity to handle traffic surges. Additionally, using Customer Managed Keys (CMKs) allows for the editing of key policies to delegate access to the centralized security account, which is impossible with default AWS managed KMS keys.

Step-by-Step Solution

1
Evaluate the database tier requirements for OLTP writes, multi-region replication, and sub-10 millisecond latencies.
Amazon DynamoDB is selected due to its ability to handle high-throughput NoSQL write traffic with single-digit millisecond latency. DynamoDB Global Tables provide active-active cross-region replication that achieves sub-second RPO and sub-minute RTO.
This satisfies the performance, latency, and disaster recovery (RTO/RPO) requirements.
2
Analyze how to scale the database for sudden, dynamic surges in read workload.
DynamoDB Auto Scaling dynamically adjusts read and write capacity units (RCUs and WCUs) based on specified utilization percentages.
This addresses the dynamic and unpredictable read surges without manual intervention or over-provisioning.
3
Determine the encryption key management strategy for cross-account security auditing.
Create a Customer Managed Key (CMK) in AWS KMS in each destination region, and configure the key policies to explicitly grant access to the auditing IAM role in the centralized security account.
AWS managed KMS keys (e.g., aws/dynamodb) do not allow policy modification and cannot be shared cross-account, necessitating the use of Customer Managed Keys.

Key Concept

Multi-region NoSQL database architecture utilizing DynamoDB Global Tables with Customer Managed KMS Keys for secure cross-account auditing and Auto Scaling for elastic performance.
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Database and Storage Strategy

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