C100DBA Application Administration Practice Question
Which connection string parameter should be used to ensure an application driver automatically discovers all members of a replica set?
⚠ Common exam trap
Candidates often select authentication or timeout parameters like 'connectTimeoutMS', wrongly believing they control how a driver discovers cluster topology.
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
✓
replicaSet
The replicaSet parameter is essential for drivers to identify the cluster name and initiate the discovery process. When this parameter is specified, the driver uses the provided seed list to perform a 'isMaster' command against the nodes, allowing it to map the entire topology. Understanding this mechanism is vital for ensuring high availability, as the driver needs to dynamically redirect operations to the new primary during automated failover events.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
maxPoolSize
Why it's wrong here
The maxPoolSize parameter controls the number of concurrent connections the driver maintains in its connection pool to the database. It does not influence the discovery process or topology monitoring of a replica set and is strictly used for performance tuning regarding resource utilization on the application host.
- ✓
replicaSet
Why this is correct
The replicaSet parameter instructs the MongoDB driver to monitor the state of the entire replica set cluster. By providing the replica set name, the driver can verify it is connecting to the correct cluster and discover all hidden, secondary, and primary nodes based on the initial seed list provided.
- ✗
wtimeoutMS
Why it's wrong here
The wtimeoutMS parameter specifies the time limit for write operations to be acknowledged by the required number of nodes in the replica set. It is a write concern setting that dictates behavior after the connection is established and has no impact on cluster discovery or initial connection logic.
- ✗
readPreference
Why it's wrong here
The readPreference parameter defines which members of the replica set the driver should target for read operations, such as primary, secondary, or nearest. It governs where data is fetched from once the connection is established but does not facilitate the initial discovery of the replica set members themselves.
About these practice questions
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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.