LPIC-2 DNS, Web and Mail Services Practice Question
This LPIC-2 practice question tests your understanding of dns, web and mail services. This is a configuration task: choose the command set that satisfies every stated requirement. Small differences — like 'secret' vs 'password' or 'transport input ssh' vs 'all' — change whether the answer is correct. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
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?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The RewriteMap file specified is missing.
Why it's wrong here
A missing RewriteMap would produce a different error, not a lock error.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that 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.
Detailed technical explanation
How to think about this question
Apache's prefork MPM uses semaphores to serialize access to shared resources like the scoreboard and accept mutex. The kernel parameters `SEMMSL` (max semaphores per array), `SEMMNS` (total semaphores system-wide), and `SEMOPM` (max operations per semop call) are set via `sysctl kernel.sem`. In high-traffic scenarios with many child processes, the default semaphore limits (e.g., `SEMMNS=128` on older systems) can be exhausted, causing Apache to fail with 'semget: No space left on device' or similar semaphore errors. Real-world fixes include increasing these limits or switching to a threaded MPM like worker or event.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
TExam Day Tips
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A small business has 20 workstations on the 192.168.1.0/24 network and one public IP from its ISP. The router uses PAT (NAT overload) so all 20 devices share one public address using different source ports. NAT questions test whether you understand the four address terms and which direction each translation applies.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
DNS, Web and Mail Services — This question tests DNS, Web and Mail Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: 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.
What should I do if I get this LPIC-2 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.