DBS-C01 Monitoring and Troubleshooting Practice Question
A company is running a self-managed MongoDB cluster on Amazon EC2. The cluster consists of three replica set members in different Availability Zones. The primary node recently experienced a crash, and the cluster failed over to a secondary. However, the new primary is showing significantly higher latency. The operations team wants to ensure that failover is fast and consistent. What should be done to improve the failover reliability?
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
✓
Use Amazon EBS io2 Block Express volumes with provisioned IOPS.
Amazon EBS io2 Block Express volumes provide high IOPS and low latency, which can significantly reduce the time required for a secondary node to catch up and become the new primary after a failover. This improves failover reliability and reduces latency spikes. Option B is incorrect: EBS Multi-Attach is designed for shared block storage across multiple instances and is not suitable for MongoDB replica sets; using it could lead to data corruption. Option C is incorrect: while instance store volumes offer high I/O performance, they are ephemeral; if the instance fails, data is lost, making them unreliable for database workloads. Option D is incorrect: EBS snapshots are for backup and disaster recovery, not for improving failover performance.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Use Amazon EBS io2 Block Express volumes with provisioned IOPS.
Why this is correct
Using Amazon EBS io2 Block Express volumes with provisioned IOPS provides high throughput and low latency, which helps the secondary node catch up quickly after a failover, reducing latency and improving reliability.
- ✗
Use Amazon EBS Multi-Attach to allow all replicas to share the same volume.
Why it's wrong here
EBS Multi-Attach allows multiple EC2 instances to attach to the same EBS volume, but this is not recommended for MongoDB replica sets because it can cause data corruption due to concurrent writes without a proper distributed locking mechanism.
- ✗
Switch to instance store volumes for better I/O performance.
Why it's wrong here
Instance store volumes provide high I/O performance but are ephemeral; data is lost if the instance stops or fails. This makes them unsuitable for a self-managed MongoDB cluster that requires persistent data.
- ✗
Configure EBS snapshots to be taken every 5 minutes.
Why it's wrong here
EBS snapshots are used for backup and recovery, not for improving failover performance. While snapshots can help restore data after a failure, they do not reduce failover time or improve the new primary's latency.
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.