DBS-C01 Monitoring and Troubleshooting Practice Question
A database engineer is troubleshooting slow query performance on an Amazon RDS for PostgreSQL instance. The instance is db.r5.large with 500 GB of General Purpose SSD (gp2) storage. CloudWatch metrics show high Read Latency and high Read IOPS, but low CPU utilization. Which TWO actions should the engineer take to improve performance?
⚠ Common exam trap
Watch out — candidates often assume Multi-AZ can serve read traffic (like in SQL Server or Oracle), but Amazon RDS for PostgreSQL Multi-AZ does not support read-only queries on the standby; only read replicas can offload reads.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a read replica and offload read queries to it.
A is correct because creating a read replica offloads read queries from the primary instance, reducing the read IOPS and read latency on the primary. This directly addresses the high Read Latency and high Read IOPS metrics without requiring a larger instance class or storage change, especially since CPU utilization is low, indicating the bottleneck is I/O, not compute.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Create a read replica and offload read queries to it.
Why this is correct
Read replicas reduce the read IOPS on the primary, which can lower latency on the primary.
- ✗
Increase the DB instance class to a larger size, such as db.r5.2xlarge.
Why it's wrong here
Larger instance provides more CPU and memory but does not directly improve storage latency.
- ✗
Enable Multi-AZ to use the standby for read traffic.
Why it's wrong here
Standby instances in Multi-AZ are not used for reads.
- ✗
Optimize queries by adding appropriate indexes.
Why it's wrong here
While indexing can reduce IOPS, the metrics suggest a storage bottleneck; indexing is application-specific and not directly indicated.
- ✓
Switch from General Purpose SSD (gp2) to Provisioned IOPS SSD (io1) with a higher IOPS rate.
Why this is correct
Provisioned IOPS provides consistent low latency for I/O-intensive workloads.
Go deeper
Related to this question
About these practice questions
Courseiva writes every DBS-C01 question from scratch — 1,663 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DBS-C01 exam.