Confusing answer

[travis-greene]

<div>First off, I love the questions. I am gaining much more knowledge. So thank you for all the work you put in. With that said, I am a bit confused with this question in timed questions – set 6:</div><div>

Category: CSAA – Design Resilient Architectures

You were hired as an IT Consultant in a startup cryptocurrency company that wants to go global with their international money transfer app. Your project is to make sure that the database of the app is highly available on multiple regions.

What are the benefits of adding Multi-AZ deployments in Amazon RDS? (Select TWO.)

A. Creates a primary DB Instance and synchronously replicates the data to a standby instance in a different Availability Zone (AZ) in a different region.

B. Provides SQL optimization.

C. It makes the database fault-tolerant to an Availability Zone failure.

D. Increased database availability in the case of system upgrades like OS patching or DB Instance scaling.

E. Significantly increases the database performance.

Now obviously, we can use process of elimination to get rid of A (a different region), B and E. However, the concern I have is with C. I thought Auora was the only one that was truly fault tolerant. If an AZ were to go down, there would be a brief disruption, correct? Looking at the documentation, fault tolerant is only mentioned with Auora, and not the rest of RDS (Amazon Aurora storage is fault-tolerant, transparently handling the loss of up to two copies of data without affecting database write availability and up to three copies without affecting read availability.).

Am I missing something here?

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[Tutorials-Dojo]

Hi Travis,

First off, the question asked about the benefits of adding “Multi-AZ deployments” in Amazon RDS. It is true that by default, RDS will only launch a single database instance in a single AZ, unlike Aurora with multiple replicas across multi-AZs.

However, it doesn’t mean that you can not make your RDS database highly available. You can certainly make it fault-tolerant to one or more AZ failure, by setting up a Multi-AZ Deployments configuration.