Question 75 test review 2 ( RDS High Available)

[Hatim Lozan]

Hello, in the question :

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?

I didn’t understand why RDS with multi AZ is not the good option, instead of read replica, in the question they did’nt talk about read performance. I see in the question that its talking about highly available and scale, with read replica we are not highly available

Thank you for your feedback

• This discussion was modified 2 years, 3 months ago by  Hatim Lozan.

[Kenneth-Samonte-Tutorials-Dojo]

Hi Hatim,

Thank you for your feedback.

I agree that the options with Multi-AZ are good for high availability.

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

[Hatim Lozan]

Hello Kenneth,

I return to you regarding the same subject and context, and this time the answer is Multi AZ instead of Read replica.

I think the questions must be more specific, because, I fail the new question I choose the read replica because its multi az,
In my mind : scalability ==> Read replica

high availability ==> Multi AZ

But from your first anwser i fail this question 🙂 could you please guide me on this or change the questions.

Tahnk you

The question I fail ( i choose read replica over multi az) :

A company recently launched its new e-commerce platform that is hosted on its on-premises data center. The webservers connect to a MySQL database. The e-commerce platform is quickly gaining popularity and the management is worried that the on-premises servers won’t be able to keep up with user traffic in the coming months. They decided to migrate the entire application to AWS to take advantage of the scalability of the cloud. The following are required for this migration:

– Improve the security of the application.

– Increase the reliability and availability of the application.

– Reduce the latency between the users and the application.

– Reduce the maintenance overhead after the migration to the cloud.

Which of the following options should the Solutions Architect implement to meet the company requirements? (Select TWO.)

[Kenneth-Samonte-Tutorials-Dojo]

Hi Hatim,

Thank you for your reply.

Choosing read-replica vs multi-AZ will depend on requirements per scenario and which is options are available.

As for this question, it is a requirement to “- Increase the reliability and availability of the application.” Therefore, you should look first to use a Multi-AZ setup, as this is for high availability.

With multi-AZ, if the master database crash or needs maintanance, you can switch to the standby instance quickly to serve as the master database.

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