VCP-DCV vSphere Performance and Scaling Practice Question
A company runs a large vSphere environment with multiple clusters using vSAN. The performance team observes that some VMs are experiencing high latency on reads. The vSAN cluster is configured with 5 hosts, each having one cache tier (NVMe) and one capacity tier (SATA SSD). The VMs are all-flash storage policies. What should the administrator check first?
⚠ Common exam trap
The trap here is that candidates often jump to network or disk group reconfiguration (options C or D) without first using the built-in performance metrics to isolate the bottleneck, or they mistakenly think disabling deduplication/compression (option A) will improve read latency when those features primarily affect capacity tier write performance and space efficiency.
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
✓
Check the vSAN cache hit ratio and verify that the cache tier size is adequate.
High read latency in an all-flash vSAN environment often indicates that the cache tier is being overwhelmed or is undersized. The cache hit ratio directly measures how often read requests are served from the fast NVMe cache versus the slower SATA SSD capacity tier. A low cache hit ratio means the capacity tier is handling too many reads, causing latency. Checking this ratio is the first diagnostic step before making configuration changes.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Disable deduplication and compression on the vSAN datastore.
Why it's wrong here
These features primarily affect writes.
- ✓
Check the vSAN cache hit ratio and verify that the cache tier size is adequate.
Why this is correct
Low cache hit ratio leads to reads from capacity tier, increasing latency.
- ✗
Reconfigure the disk groups to use multiple cache devices.
Why it's wrong here
Multiple cache devices may not improve hit ratio.
- ✗
Increase the network bandwidth between hosts.
Why it's wrong here
Network is not the first suspect for read latency.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.