C100DBA Philosophy and Features Practice Question
A company is migrating from a monolithic SQL database to MongoDB. They want to maintain high availability. Which feature is most critical to their success?
⚠ Common exam trap
Candidates frequently confuse 'Sharding' (for horizontal scaling) with 'Replica Sets' (for high availability). They mistakenly choose sharding when the primary goal is just maintaining uptime.
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
✓
Automatic failover via Replica Sets.
High availability in MongoDB is primarily achieved through Replica Sets. A replica set consists of multiple nodes that store the same data, providing redundancy and automatic failover. If the primary node becomes unavailable, the replica set automatically elects a new primary, ensuring the application remains accessible. This architecture is fundamental to MongoDB's design philosophy of providing a resilient system that can withstand infrastructure failures without impacting the client application's availability.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Horizontal sharding of the data.
Why it's wrong here
Sharding is used for horizontal scalability by distributing data across multiple machines. While it helps with large datasets and throughput, it does not inherently provide high availability. A sharded cluster still relies on replica sets for each shard to ensure that data remains available if a node fails.
- ✓
Automatic failover via Replica Sets.
Why this is correct
Replica Sets are the core mechanism for high availability. They provide data redundancy across multiple nodes and use an automated heartbeat and election process to promote a secondary node if the primary goes down, ensuring continuous operation and minimizing downtime for critical enterprise applications.
- ✗
The use of the Aggregation Framework.
Why it's wrong here
The Aggregation Framework is a powerful tool for data processing and analysis within MongoDB. While it is essential for complex queries and data transformation, it has no impact on high availability or system redundancy. It is an application-side feature rather than an infrastructure or architectural resilience feature.
- ✗
Strict enforcement of ACID transactions.
Why it's wrong here
While MongoDB supports multi-document ACID transactions, this feature ensures data integrity and consistency, not service availability. Availability is a function of the deployment topology and automated recovery mechanisms, whereas transactions are a feature of the database's consistency model, which operate independently of the node's uptime.
About these practice questions
This C100DBA question is part of Courseiva's 222-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official MongoDB exam blueprint
This C100DBA practice question is part of Courseiva's free MongoDB 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 C100DBA exam.