A customer has a 10 GB AWS Direct Connect connection to an AWS region where they have a
web application hosted on Amazon Elastic Computer Cloud (EC2). The application has
dependencies on an on-premises mainframe database that uses a BASE (Baste Available, Soft
state, Eventual consistency) rather than an ACID (Atomicity, Consistency, Isolation, Durability)
consistency model. The application is exhibiting undesirable behavior because the database is
not able to handle the volume of writes. How can you reduce the load on your on-premises
database resources in the most cost-effective way?
A.
Provision an RDS read-replica database on AWS to handle the writes and synchronize the two
databases using Data Pipeline.
B.
Modify the application to use DynamoDB to feed an EMR cluster which uses a map function to
write to the on-premises database.
C.
Modify the application to write to an Amazon SQS queue and develop a worker process to flush
the queue to the on-premises database.
D.
Use an Amazon Elastic Map Reduce (EMR) S3DistCp as a synchronization mechanism between
the on- premises database and a Hadoop cluster on AWS.
Explanation:
https://aws.amazon.com/sqs/faqs/
Correct Answer C.
A. Provision an RDS read-replica database on AWS to handle the writes and synchronize the two databases
using Data Pipeline.
— RDS read-replica are for MySQL, MariaDB, and PostgreSQL. Not applicable here. Easily ruled out.
The correct answer should be :
B. Modify the application to use DynamoDB to feed an EMR cluster which uses a map function to write to the on-premises database.
— I think the DynamoDB here is just to distract and focus on BASE. It may be suitable but it complicates and there is additional cost.
C. Modify the application to write to an Amazon SQS queue and develop a worker process to flush the queue
to the on-premises database.
i) Its BASE so we can use SQS and there is no hurry to write/read the data – Eventual consistency model.
ii) cost effective as that is the only item that is introduced here.
D. Use an Amazon Elastic Map Reduce (EMR) S3 DistCp as a synchronization mechanism between the onpremises database and a Hadoop cluster on AWS.
–Not cost effective