NFS Port Binding for Performance
An administrator is troubleshooting a VM that is experiencing high latency on its virtual disks. The VM is connected to a vSphere datastore backed by an NFS share. The ESXi host has multiple VMkernel ports configured for NFS traffic. Which configuration change is most likely to improve storage performance?
Quick Answer
The correct answer is to configure multiple VMkernel ports for NFS and enable port binding with a route based on originating port ID policy. This works because NFS port binding, also known as NFS multipathing, allows the ESXi host to actively use multiple VMkernel ports for NFS traffic, and the originating port ID policy distributes individual virtual machine I/O requests across different physical NICs and paths. By spreading the load, you prevent a single VMkernel port or physical link from becoming a bottleneck, which directly reduces latency and increases aggregate throughput for the VM’s virtual disks. On the VCP-DCV exam, this scenario tests your understanding of NFS performance optimization and the distinction between simple multiple VMkernel ports (which are passive) versus port binding with active load balancing. A common trap is thinking that just adding more VMkernel ports improves performance—without port binding and the correct load-balancing policy, only one port is active at a time. Memory tip: think “Port Binding = Ports in Action” to remember that binding makes all ports work simultaneously.
⚠ Common exam trap
Watch out — candidates often assume jumbo frames (Option C) are the universal fix for storage latency, but they overlook that NFS port binding directly addresses the root cause of network congestion by enabling multipathing, which is the specific technology tested in this VCP-DCV domain.
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
✓
Configure multiple VMkernel ports for NFS and enable port binding with a route based on originating port ID policy.
NFS port binding (also known as NFS multipathing) allows multiple VMkernel ports to be used for NFS traffic, and when combined with a 'route based on originating port ID' load-balancing policy, it enables the ESXi host to distribute NFS I/O across multiple physical NICs and paths. This increases aggregate throughput and reduces latency by avoiding congestion on a single VMkernel port or physical link, which is the most effective change for improving storage performance in this scenario.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Configure multiple VMkernel ports for NFS and enable port binding with a route based on originating port ID policy.
Why this is correct
This leverages multiple network paths to improve performance and redundancy.
- ✗
Use a single VMkernel port for NFS and configure it with the highest priority.
Why it's wrong here
Single port can become a bottleneck; multiple ports with load balancing are better.
- ✗
Enable jumbo frames on the NFS VMkernel port and the physical switches.
Why it's wrong here
Jumbo frames can improve performance but require end-to-end support and may not resolve latency issues.
- ✗
Increase the disk queue depth on the VM's virtual SCSI controller.
Why it's wrong here
This might increase throughput but does not address network latency.
Go deeper
Related to this question
About these practice questions
This VCP-DCV question is part of Courseiva's 498-question bank — original exam-style content with full explanations and wrong-answer analysis, never real exam questions or exam dumps. Learn why practice questions differ from exam dumps →
Same concept, more angles
1 more way this is tested on VCP-DCV
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. An administrator notices that a virtual machine on an NFS datastore is experiencing intermittent performance degradation. The ESXi hosts are connected to the NFS server via a 10 GbE network. The administrator uses esxtop and sees high average latency on the storage device, but the NFS server reports low latency. What is the most likely cause?
hard- A.Jumbo frames are enabled on the ESXi hosts but not on the NFS server
- ✓ B.Network congestion is causing TCP retransmissions
- C.The NFS server is performing data deduplication on the datastore
- D.The NFS datastore is mounted with read-only permissions
Why B: When ESXi reports high latency but the NFS server reports low latency, it suggests that the latency is occurring on the network between them. TCP retransmissions caused by network congestion or packet loss can increase latency as seen by ESXi, while the NFS server may complete requests quickly and not observe the delay. Option A is incorrect because jumbo frame misconfiguration would likely cause connectivity issues, not intermittent performance degradation with low server-side latency. Option C is incorrect because deduplication on the server would affect server-side latency, not cause a discrepancy between ESXi and server latency. Option D is incorrect because read-only permissions would result in write failures, not high latency.
JA
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.