Questions 22 to 24

Question 22

A solutions architect is creating a design for a two-tier application with a MySQL RDS back-end. The performance requirements of the database tier are hard to quantify until the application is running, and the architect is concerned about right-sizing the database.

What methods of scaling are possible after the MySQL RDS database is deployed? (Select TWO)

1. Vertical scaling for read and write by choosing a larger instance size
2. Horizontal scaling for write capacity by enabling Multi-AZ
3. Vertical scaling for read and write by using Transfer Acceleration
4. Horizontal scaling for read and write by enabling Multi-Master RDS DB
5. Horizontal scaling for read capacity by creating a Read-Replica

Correct Answer: 1, 5

Explanation: To handle a higher load in your database, you can vertically scale up your master database with a simple push of a button. In addition to scaling your master database vertically, you can also improve the performance of a read-heavy database by using Read Replicas to horizontally scale your database.

CORRECT: “Vertical scaling for read and write by choosing a larger instance size” is a correct answer.

INCORRECT: “Horizontal scaling for write capacity by enabling Multi-AZ” is incorrect. You cannot scale write capacity by enabling Multi-AZ as only one DB is active and can be written to.

INCORRECT: “Vertical scaling for read and write by using Transfer Acceleration” is incorrect. Transfer Acceleration is a feature of S3 for fast uploads of objects.

INCORRECT: “Horizontal scaling for read and write by enabling Multi-Master RDS DB” is incorrect. There is no such thing as a Multi-Master MySQL RDS DB (there is for Aurora).

CORRECT: “Horizontal scaling for read capacity by creating a Read-Replica” is also a correct answer.

References: https://aws.amazon.com/blogs/database/scaling-your-amazon-rds-instance-vertically-and-horizontally/