AWS Certified Database – Specialty — Question 1

A Database Specialist is troubleshooting an application connection failure on an Amazon Aurora DB cluster with multiple Aurora Replicas that had been running with no issues for the past 2 months. The connection failure lasted for 5 minutes and corrected itself after that. The Database Specialist reviewed the Amazon
RDS events and determined a failover event occurred at that time. The failover process took around 15 seconds to complete.
What is the MOST likely cause of the 5-minute connection outage?

Answer options

• A. After a database crash, Aurora needed to replay the redo log from the last database checkpoint
• B. The client-side application is caching the DNS data and its TTL is set too high
• C. After failover, the Aurora DB cluster needs time to warm up before accepting client connections
• D. There were no active Aurora Replicas in the Aurora DB cluster

Correct answer: B

Explanation

The most likely reason for the 5-minute connection outage is that the client-side application is caching the DNS data, which has a high TTL, leading to delays in resolving the new endpoint after the failover. Answer A is incorrect as Aurora's recovery from a crash is typically faster than 5 minutes. Answer C is not valid because Aurora is designed to quickly become available post-failover. Answer D is also incorrect since the presence of multiple Aurora Replicas would prevent a total outage.