C100DBA Server Administration Practice Question
Network Topology
Refer to the exhibit. An administrator attempts to recover a corrupted standalone mongod instance using the --repair flag. Based on the error log output, what is the most appropriate next step for the administrator?
⚠ Common exam trap
Candidates often rely on --repair as a 'fix-all' solution, not realizing that severe corruption, such as short reads, indicates physical data loss that repair cannot resolve.
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
✓
Restore the data files from the most recent known-good backup.
The --repair flag is a last-resort tool that attempts to salvage data from corrupted files, but it cannot fix severe filesystem or metadata corruption where blocks are missing or unreadable. The 'Short read' error indicates physical or logical corruption that WiredTiger cannot bypass. In this scenario, restoring from a known-good backup is the only reliable way to ensure data integrity.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Run the --repair command again with the --wiredTigerEngineConfig option.
Why it's wrong here
Running the repair command a second time with different engine configurations will not resolve a 'Short read' error, which indicates that the underlying data blocks are physically missing or inaccessible. Additional flags cannot reconstruct data that the storage engine cannot physically read from the disk subsystem.
- ✗
Delete the mongod.lock file and restart the server normally.
Why it's wrong here
Deleting the lock file and attempting a normal restart is dangerous and will likely fail if the data files are corrupted. The 'Short read' error already proves that the data files are in an inconsistent state, and bypassing the repair process could lead to further data loss or silent corruption.
- ✓
Restore the data files from the most recent known-good backup.
Why this is correct
Since the --repair process failed with a critical WiredTiger read error, the data files are too corrupted for the built-in tools to salvage. The most reliable and standard administrative response is to wipe the corrupted directory and restore the database from a verified backup to ensure consistency.
- ✗
Manually edit the WiredTiger.wt file to fix the offset error.
Why it's wrong here
The internal structure of WiredTiger data files is complex and binary. Attempting to manually edit these files with a hex editor or other tools is not supported and is virtually certain to cause total data loss. Administrators should never attempt to modify MongoDB data files directly outside of official tools.
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.