You are working on a client application that uses DynamoDB as its database to store IoT sensor data. The application is receiving ProvisionedThroughputExceededException too frequently for read requests. The client has asked you to overcome this issue by adjusting RCUs. The application receives 1200 eventual read requests every minute where each request is of 2.5KB. How many RCUs does the application need to fulfill all the requests?

Answer options:

A.10
B.11
C.20
D.9

Correct Answer: A
Option A is correct: 1 RCU provides two 4KB read per second for the eventual consistency model.
Items to read every second: 1200/60 = 20
To read one item, we need: 2.5/4 = 0.63, rounding off to the nearest whole number will be 1. Hence, we require 1 RCUs to read one item.
Total RCUs required: 1*20 = 20; 20/2 = 10, because eventual consistency model provides us 2 4KB read every second.
Option B, C and D are incorrect since they are not the required RCUs to overcome ProvisionedThroughputExceededException error.
Reference: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/HowItWorks.ReadWriteCapacityMode.html