VCP-DCV vSphere Performance and Scaling Practice Question
A vSphere administrator is troubleshooting a VM that is experiencing excessive disk latency. The VM is on a datastore accessed via NFS over a 1GbE network. The host shows high network utilization. Which action should be taken to improve performance?
⚠ Common exam trap
It's easy for candidates to assume Storage I/O Control (SIOC) can solve any storage latency issue, but SIOC only manages contention at the storage array level, not network bandwidth limitations, which is the actual bottleneck in this NFS scenario.
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
✓
Upgrade the network link to 10GbE or enable multiple NICs with teaming.
The VM is experiencing excessive disk latency due to high network utilization on the 1GbE link. Since NFS storage traffic is entirely network-bound, upgrading to 10GbE or enabling multiple NICs with teaming increases the available bandwidth, reduces congestion, and directly addresses the root cause of the latency. This is the most effective action because the bottleneck is at the network layer, not the storage protocol or VM configuration.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Enable Storage I/O Control on the datastore.
Why it's wrong here
Storage I/O Control throttles and prioritises datastore I/O during contention; it does not increase the 1GbE link capacity that is saturated, so latency persists. It is tempting because SIOC addresses noisy-neighbour latency, and it would be correct when multiple VMs contend for a datastore that still has spare bandwidth.
- ✗
Convert the datastore from NFS to VMFS.
Why it's wrong here
VMFS is block storage, so converting replaces the NFS transport rather than adding bandwidth; the 1GbE link remains the constraint and the migration itself is disruptive. It is tempting because VMFS suits block workloads, and it would be correct when NFS-specific protocol overhead, not link saturation, causes the latency.
- ✗
Increase the memory reservation for the VM.
Why it's wrong here
Memory reservation governs RAM allocation and swap behaviour, not the network throughput carrying NFS traffic, so it cannot relieve the 1GbE saturation causing latency. It is tempting because reservations help memory-constrained VMs, and it would be correct where ballooning or swapping, not storage transport, is the bottleneck.
- ✓
Upgrade the network link to 10GbE or enable multiple NICs with teaming.
Why this is correct
NFS traffic traverses the 1GbE link, so high network utilisation saturates the path and inflates disk latency. Upgrading to 10GbE, or teaming multiple NICs, raises aggregate throughput and relieves that bottleneck, directly addressing the constrained network link.
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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.