Troubleshooting network performance issues in a vSphere environment
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Troubleshooting network performance issues in a vSphere environment

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Article ID: 310446

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Updated On:

Products

VMware vCenter Server VMware vSphere ESXi

Issue/Introduction

Networking performance both to and from the ESXi host and/or virtual machines is not optimal.

Environment

  • VMware vCenter Server 7.x
  • VMware vCenter Server 8.x
  • VMware vCenter Server 9.0.x

Cause

Network problems can have several causes: 

  • Resource shares for virtual machine network  are too few
  • Network packet size (MTU) is too large, which may result in high network latency
  • Network packet size (MTU) is too small, which may increase the demand for CPU resources needed for processing of each packet

Resolution

The following ESXi host components can contribute to network performance:

  • Validate that each troubleshooting step below is valid for the environment
  • Each step provides instructions or links to a document for validating and taking corrective action as necessary
  • Steps are ordered in the correct sequence to isolate the issue and identify the proper resolution
  • Please do not skip a step
  1. Verify that the latest version of VMware Tools is installed in the virtual machines
  2. Verify the appropriate network driver for the virtual machine based on environmental needs
  3. VMware recommends using multiple NICs on the associated virtual switch to increase the overall network capacity for portgroups that contain many virtual machines or several virtual machines that are very active on the network. 
  4. Verify the speed and duplex settings of the installed network adapters
  5. Verify that the portgroup and virtual switch are not configured for promiscuous mode
  6. Verify that Jumbo Frames settings are consistent across the VM, vSwitch and the physical switch
  7. Verify if the Driver/Firmware versions are compatible according to the VMware Compatibility Guide
    • Check the IOVP (I/O Vendor Program) certified drivers
  8. Verify if the packets are being sent/received at the ESXi Host layer