DBS-C01 Question #277: Real Exam Question with Answer & Explanation

Question

A company is using an Amazon RDS Multi-AZ DB instance in its development environment. The DB instance uses General Purpose SSD storage. The DB instance provides data to an application that has I/O constraints and high online transaction processing (OLTP) workloads. The users report that the application is slow. A database specialist finds a high degree of latency in the database writes. The database specialist must decrease the database latency by designing a solution that minimizes operational overhead. Which solution will meet these requirements?

Options

• AEliminate the Multi-AZ deployment. Run the DB instance in only one Availability Zone
• BRecreate the DB instance. Use the default storage type. Reload the data from an automatic
• CSwitch the storage to Provisioned IOPS SSD on the DB instance that is running
• DRecreate the DB instance. Use Provisioned IOPS SSD storage. Reload the data from an

Explanation

To decrease high write latency and address I/O constraints on an Amazon RDS Multi-AZ instance experiencing slow application performance with OLTP workloads, modify the storage type to Provisioned IOPS SSD.

Common mistakes.

• A. Eliminating Multi-AZ deployment reduces database availability and durability without directly addressing the root cause of high write latency due to I/O constraints, and is generally not a recommended practice for production or critical development environments.
• B. Recreating the DB instance and reloading data from a snapshot would incur significant downtime and operational overhead, and using 'default storage type' might still result in General Purpose SSD, which has already proven insufficient for the workload.
• D. While Provisioned IOPS SSD is the correct storage type, recreating the DB instance and reloading data from a snapshot involves considerably more operational overhead and downtime than simply modifying the storage type of the existing instance, which can be done with minimal interruption.

Concept tested. Optimizing RDS storage for OLTP workloads

Reference. https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/CHAP_Storage.html#Concepts.Storage.PIOPS

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