Timed Mode Set 2 – Question 18

[AJam]

Hi

For the below question, why is the following answer incorrect? The question states that the SA must ensure that this infrastructure is highly-available and scalable enough to handle web traffic fluctuations automatically?

“Run the web and application tiers in stateless instances in an autoscaling group, using Elasticache Memcached for tier synchronization and CloudWatch for monitoring. Run the database tier using RDS with Multi-AZ enabled.”

Question is below:

A hospital chain in London uses an online central hub for its doctors and nurses. The application interacts with millions of requests per day to fetch various medical data of their patients. The system is composed of a web tier, an application tier, and a database tier that receives large and unpredictable traffic demands. The Solutions Architect must ensure that this infrastructure is highly-available and scalable enough to handle web traffic fluctuations automatically.

Which of the following options should the solutions architect implement to meet the above requirements?A hospital chain in London uses an online central hub for its doctors and nurses. The application interacts with millions of requests per day to fetch various medical data of their patients. The system is composed of a web tier, an application tier, and a database tier that receives large and unpredictable traffic demands. The Solutions Architect must ensure that this infrastructure is highly-available and scalable enough to handle web traffic fluctuations automatically.

Which of the following options should the solutions architect implement to meet the above requirements?

[Kenneth-Samonte-Tutorials-Dojo]

Hello AJam,

Thank you for your feedback.

The question specifically asks for “highly-available and scalable enough to handle web traffic fluctuations automatically”.

For scalability AWS recommends read-replicas, and for high-availability it is multi-AZ.

You can create multiple read-replicas on different AZ for high-availability, and you can even also promote the read replica to be the master database.

For the given choices, we should choose the answer that can solve as many of the required items as possible.

Run the web and application tiers in stateful instances in an autoscaling group, using CloudWatch for monitoring. Run the database tier using RDS with Multi-AZ enabled.

>> This is incorrect because there will be millions of requests so you may want to create a caching tier with Elasticache or Redis – A caching tier also improves the performance of the application as it can reduce the load on the master database, which can improve availability too.

Hope this helps.

Let us know if you need further assistance. The Tutorials Dojo team is dedicated to helping you pass your AWS exam!

Regards,

Kenneth Samonte @ Tutorials Dojo