C100DBA Application Administration Practice Question
A MongoDB application requires that reads never see data that could be rolled back, even in the event of a replica set failover. The application also needs to read from secondary nodes to distribute load. Which read concern should be used with a secondary read preference?
⚠ Common exam trap
The trap here is thinking that "linearizable" is the only read concern that prevents rollback, but it cannot be used with secondary reads. "majority" read concern also prevents rollback and works with secondaries.
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
✓
"majority"
The application needs to read from secondaries while ensuring that the data returned is not subject to rollback. "majority" read concern guarantees that the data has been acknowledged by a majority of replica set members, making it durable across failover. It is compatible with secondary read preferences, unlike "linearizable", which requires primary reads. Therefore, "majority" is the correct choice.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
"majority"
Why this is correct
"majority" read concern ensures that the data returned has been acknowledged by a majority of replica set members. When used with a secondary read preference, it guarantees that the data read from the secondary is durable and cannot be rolled back during failover. This meets the application's requirement of never seeing rollback-able data.
- ✗
"linearizable"
Why it's wrong here
"linearizable" read concern provides the strongest consistency by reading from the primary and ensuring the data is majority-committed. However, it cannot be used with a secondary read preference because it requires reading from the primary. The application needs to read from secondaries, so "linearizable" is not applicable.
- ✗
"available"
Why it's wrong here
"available" read concern returns data without any durability guarantees and is intended for sharded clusters where consistency is not critical. It does not ensure that the data has been replicated to a majority, so it can return rollback-able data. This does not satisfy the application's requirement for durable reads.
- ✗
"local"
Why it's wrong here
"local" read concern returns data from the queried instance without guaranteeing that it has been replicated to a majority of members. If the primary fails, the data might be rolled back. Since the application requires that reads never see rollback-able data, "local" is insufficient, especially when reading from secondaries.
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.