C100DBA Server Administration Practice Question
When adding a new node to an existing replica set, what is the primary factor that determines how quickly the new member will be able to begin participating in elections?
⚠ Common exam trap
Candidates often guess hardware parameters like CPU speed or RAM size as the primary sync factor, ignoring that dataset volume and network transfer rates dictate initial sync duration.
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
✓
The amount of data in the dataset and network bandwidth.
The speed at which a new replica set member becomes 'secondary' and ready to participate depends on the amount of data it must synchronize from an existing member. Initial sync involves cloning data and applying the oplog. Understanding this process is vital for capacity planning, as adding a large member can put significant I/O and network pressure on the current primary or secondaries, potentially impacting performance for existing application traffic during the synchronization process.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The memory limit set in the configuration file.
Why it's wrong here
While memory is important for general performance, the initial sync speed is primarily bound by network bandwidth and disk I/O throughput. The memory configuration does not directly accelerate the bulk data transfer required to populate the new node's data directory from an existing node's snapshot.
- ✓
The amount of data in the dataset and network bandwidth.
Why this is correct
The new member must copy the entire dataset from an existing member before it can apply the oplog to catch up. The time taken for this process is directly proportional to the total size of the data and the speed of the network connection between the nodes.
- ✗
The number of users defined in the admin database.
Why it's wrong here
User authentication data is replicated just like any other collection. The number of users is negligible compared to the overall data size and has no measurable impact on the time required to complete the initial synchronization process when adding a new node to a replica set.
- ✗
The version of the MongoDB shell used.
Why it's wrong here
The MongoDB shell is a client-side tool and has no impact on the server-side process of data synchronization. Whether an administrator uses the shell or a driver to add the node, the synchronization speed is strictly a factor of the server's backend performance and data volume.
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.