- A
Some processes have open file handles to the deleted files, preventing the space from being released.
When a file is deleted but still open, the space is not freed until the file handle is closed. Use lsof to identify the processes.
- B
The disk quota for the mysql user is exceeded, so deletions do not reduce usage.
Why wrong: Disk quotas limit usage but do not cause deletions to not free space; after deletion, quota usage decreases.
- C
The SSD is not TRIM-enabled, so deleted blocks are not reclaimed.
Why wrong: TRIM is an optimization for SSDs; lack of TRIM does not prevent space from being freed when files are deleted; the space becomes available immediately.
- D
The filesystem was remounted read-only due to errors, so deletions are not permanent.
Why wrong: If the filesystem were remounted read-only, df would still reflect the usage before remount, and deletions would fail. But the administrator said deletions succeeded (df unchanged).
LPIC-1 Devices, Filesystems and FHS Practice Question
This LPIC-1 practice question tests your understanding of devices, filesystems and fhs. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
You are the system administrator for a small business running a Red Hat Enterprise Linux 8 server that hosts a MySQL database and a web server. The server has two physical disks: a 240GB SSD (sda) with partitions sda1 (boot), sda2 (root), sda3 (swap), and a 1TB HDD (sdb) with a single partition sdb1 mounted at /var/lib/mysql. The server has been running for months without issues. However, this morning you receive alerts that the MySQL database is not accepting new connections. You log in and find that the /var filesystem is 100% full. You check the disk usage and see that /var/lib/mysql uses 90% of the space, but there are also large log files in /var/log/httpd. To free up space immediately and restore database service while planning a permanent solution, you decide to compress old log files and move some database archives to a backup server. After compressing several log files with gzip, the available space increases by only a few MB. You then delete some old database backups from /var/lib/mysql/backup, but the space usage shown by df remains unchanged. What is the most likely cause of this behavior?
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.
Clue:
"immediately / without restart"Why it matters: Time or reboot constraint — the correct answer must take effect right away without requiring a reboot or reload.
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
Some processes have open file handles to the deleted files, preventing the space from being released.
When a file is deleted but still held open by a running process (e.g., the MySQL daemon or httpd), the filesystem does not release the disk space until all file handles are closed. In this scenario, the large log files in /var/log/httpd were compressed with gzip, but the original uncompressed files may still be open by the web server process, so deleting them (or the old database backups) does not free space until the process is restarted or the handles are released. This explains why df still shows 100% usage despite the deletions.
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.
- ✓
Some processes have open file handles to the deleted files, preventing the space from being released.
Why this is correct
When a file is deleted but still open, the space is not freed until the file handle is closed. Use lsof to identify the processes.
Clue confirmation
The clue words "most likely", "immediately / without restart" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The disk quota for the mysql user is exceeded, so deletions do not reduce usage.
Why it's wrong here
Disk quotas limit usage but do not cause deletions to not free space; after deletion, quota usage decreases.
- ✗
The SSD is not TRIM-enabled, so deleted blocks are not reclaimed.
Why it's wrong here
TRIM is an optimization for SSDs; lack of TRIM does not prevent space from being freed when files are deleted; the space becomes available immediately.
- ✗
The filesystem was remounted read-only due to errors, so deletions are not permanent.
Why it's wrong here
If the filesystem were remounted read-only, df would still reflect the usage before remount, and deletions would fail. But the administrator said deletions succeeded (df unchanged).
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates assume deleting files immediately frees space on disk, overlooking the fact that open file handles by running processes can retain the data blocks until the handles are closed.
Detailed technical explanation
How to think about this question
Under Linux, the kernel maintains a reference count for each inode; when a file is deleted via unlink(), the directory entry is removed, but the inode and its data blocks are not freed until the last file descriptor referencing that inode is closed. This is commonly seen with log files rotated or deleted while a daemon like httpd or mysqld still holds them open, and can be verified with lsof | grep '(deleted)' or by checking /proc/<PID>/fd/. A real-world fix often involves sending a SIGHUP or restarting the service to release the handles.
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 practitioner preparing for the LPIC-1 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
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.
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Devices, Filesystems and FHS — study guide chapter
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FAQ
Questions learners often ask
What does this LPIC-1 question test?
Devices, Filesystems and FHS — This question tests Devices, Filesystems and FHS — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Some processes have open file handles to the deleted files, preventing the space from being released. — When a file is deleted but still held open by a running process (e.g., the MySQL daemon or httpd), the filesystem does not release the disk space until all file handles are closed. In this scenario, the large log files in /var/log/httpd were compressed with gzip, but the original uncompressed files may still be open by the web server process, so deleting them (or the old database backups) does not free space until the process is restarted or the handles are released. This explains why df still shows 100% usage despite the deletions.
What should I do if I get this LPIC-1 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", "immediately / without restart". 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.
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Last reviewed: Jun 25, 2026
This LPIC-1 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-1 exam.
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