The answer is that the virtual disk is thin-provisioned, so only the actual written blocks consume space on the datastore. This discrepancy occurs because thin provisioning creates a virtual disk file (VMDK) that starts small and grows only as the guest OS writes data, meaning the datastore reports physical consumption of 800 GB while the guest OS logically reports 1.5 TB of used space based on its file system metadata. On the VCP-DCV exam, this scenario tests your understanding of storage provisioning differences and how VMFS6 handles thin VMDKs; a common trap is confusing guest OS logical usage with datastore physical usage. Remember the key distinction: the guest sees allocated space, the datastore sees written blocks. A helpful memory tip is “Guest reports what it thinks it owns; the datastore reports what it actually holds.”
VCP-DCV Configure and Manage vSphere Storage Practice Question
This VCP-DCV practice question tests your understanding of configure and manage vsphere storage. 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.
A vSphere administrator is observing that a VM with a 2 TB thin-provisioned virtual disk on a VMFS6 datastore is reporting 1.5 TB of used space inside the guest OS, but the datastore shows only 800 GB consumed by the VM. What is the most likely cause of this discrepancy?
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 virtual disk is thin-provisioned, so only the actual written blocks consume space on the datastore.
The discrepancy is because the virtual disk is thin-provisioned. Thin provisioning means the virtual disk file (VMDK) on the datastore only occupies space for blocks that have been written to by the guest OS, not the full allocated size. The guest OS reports 1.5 TB of used space because it sees the logical file system usage, but the datastore only shows 800 GB consumed because that is the actual physical storage used by the written blocks.
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 virtual disk needs to be defragmented to reclaim space.
Why it's wrong here
Defragmentation does not affect datastore allocation.
✗
The VM has a snapshot that is consolidating, reducing storage usage.
Why it's wrong here
Snapshots increase storage usage, not decrease.
✗
The virtual disk is thick-provisioned lazy zeroed, which delays allocation.
Why it's wrong here
Thick lazy zeroed still allocates all space at creation.
✓
The virtual disk is thin-provisioned, so only the actual written blocks consume space on the datastore.
Why this is correct
Thin provisioning allocates space as data is written.
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.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates may confuse guest OS reported usage with datastore consumption, not realizing that thin provisioning only allocates storage for blocks actually written, leading them to incorrectly suspect snapshots or defragmentation issues.
Detailed technical explanation
How to think about this question
Thin provisioning on VMFS6 uses the Space Efficient Virtual Disk (SE Sparse) format for improved UNMAP support, allowing the guest OS to reclaim unused blocks via SCSI UNMAP commands. However, the guest OS file system reports used space based on its own metadata (e.g., NTFS or ext4), which includes deleted files still in the recycle bin or unlinked inodes, while the hypervisor only tracks blocks physically written to the VMDK. In real-world scenarios, this discrepancy can also be caused by guest OS file system fragmentation or lack of TRIM/UNMAP support, but the core reason here is thin provisioning.
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 VCP-DCV 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.
Configure and Manage vSphere Storage — This question tests Configure and Manage vSphere Storage — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The virtual disk is thin-provisioned, so only the actual written blocks consume space on the datastore. — The discrepancy is because the virtual disk is thin-provisioned. Thin provisioning means the virtual disk file (VMDK) on the datastore only occupies space for blocks that have been written to by the guest OS, not the full allocated size. The guest OS reports 1.5 TB of used space because it sees the logical file system usage, but the datastore only shows 800 GB consumed because that is the actual physical storage used by the written blocks.
What should I do if I get this VCP-DCV 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 VCP-DCV practice question is part of Courseiva's free VMware 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 VCP-DCV 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.