Q9 — AWS SOA-C02 Ch.1

Question 9 of 100 | ← Chapter 1

A company has applications that process transaction requests multiple times each minute. The applications write transaction data to a single Amazon RDS DB instance. As the company begins to process more transactions, the company becomes concerned that it has no failover solution in place for disaster recovery (DR). The company needs the DB instance to fail over automatically without losing any committed transactions. Which solution will meet these requirements?

• A. Create an RDS read replica in the same AWS Region. Configure an AWS Lambda function to promote the replica as the primary DB instance during a DR scenario.
• B. Create an RDS read replica in a different AWS Region. Configure an AWS Lambda function to promote the replica as the primary DB instance during a DR scenario.
• C. Modify the DB instance to be a Multi-AZ deployment. ✓
• D. Setup an Amazon CloudWatch alarm that monitors the DB instance memory utilization with a threshold greater than 90%. Invoke an AWS Lambda function to restart the DB instance.

Correct Answer: C. Modify the DB instance to be a Multi-AZ deployment.

Explanation

该问题描述了一个公司使用Amazon RDS DB实例处理大量交易请求的场景，随着交易量的增加，公司担心在灾难发生时没有容灾恢复的解决方案。关键需求是在灾难恢复过程中，数据库实例能够自动切换，且不能丢失任何已提交的交易。 分析各选项： A选项，在同一AWS Region创建RDS读副本并配置AWS Lambda函数在DR场景中提升副本为主DB实例，这种方式可以提供一定的容灾能力，但无法确保在主DB实例故障时，已提交的事务不会丢失。 B选项，在不同AWS Region创建RDS读副本并做相同配置。虽然这增加了容灾的能力，但在自动故障转移和事务保证方面仍存在不足。 C选项，将DB实例修改为Multi-AZ部署。这是AWS提供的一种服务，可以自动进行故障检测和转移，且能保证在故障转移过程中不会丢失已提交的事务。这完全符合公司对于灾难恢复的需求。 D选项，设置Amazon CloudWatch警报来监控DB实例内存使用率，并配置阈值及AWS Lambda函数进行重启操作。这主要关注的是性能监控和优化，与自动故障切换和事务保证无直接关系。 因此，根据问题和选项的分析，选项C是满足公司需求的最佳解决方案。