LPIC-2 DNS, Web and Mail Services Practice Question
Exhibit
[crit] (28)No space left on device: mod_rewrite: could not create rewrite_log_lock
Refer to the exhibit. What is the most likely cause of this Apache error?
⚠ Common exam trap
Watch out — candidates often confuse semaphore errors with disk space or memory issues, but LPIC-2 specifically tests knowledge of IPC resource limits and their impact on Apache MPM behavior.
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 semaphore limit for the Apache user is exceeded.
The Apache error 'semaphore limit exceeded' occurs when the number of semaphores allocated to the Apache user exceeds the system-wide or per-user semaphore limit. Apache uses semaphores for inter-process communication (IPC) in its prefork or worker MPMs to coordinate child processes. The correct answer is C because this error directly indicates that the kernel's semaphore limits (e.g., `SEMMSL`, `SEMMNS`, or `SEMOPM` in `/proc/sys/kernel/sem`) have been exhausted for the Apache user, often due to too many child processes or a misconfigured `MaxClients` directive.
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 filesystem containing the logs is full.
Why it's wrong here
A full filesystem would affect log file creation, but the error is specifically about a rewrite_log_lock, which uses semaphores.
- ✗
The server is out of memory.
Why it's wrong here
Out of memory would cause swapping or OOM killer, not a 'No space left on device' error.
- ✓
The semaphore limit for the Apache user is exceeded.
Why this is correct
Apache uses semaphores for lock files; exhausting semaphore limits causes this error.
- ✗
The RewriteMap file specified is missing.
Why it's wrong here
A missing RewriteMap would produce a different error, not a lock error.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This LPIC-2 practice question is part of Courseiva's free LPI 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 LPIC-2 exam.