Migrating ESXi Network Connectivity from Fiber SFP to Copper SFP
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Migrating ESXi Network Connectivity from Fiber SFP to Copper SFP

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Article ID: 435648

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Updated On:

Products

VMware vSphere ESXi

Issue/Introduction

  • Users need to migrate existing ESXi network connectivity from Optical Fiber SFP NICs to Copper SFP NICs without losing connectivity to virtual machines (VMs) or access to backend storage (NAS/VMDKs).

Purpose

This article provides a recommended procedure and prerequisites for transitioning from fiber to copper interfaces while maintaining network stability and ensuring a successful failover.
Users need to migrate existing ESXi network connectivity from Optical Fiber SFP NICs to Copper SFP NICs without losing connectivity to virtual machines (VMs) or access to backend storage (NAS/VMDKs).

Environment

VMware ESXi

Resolution

Prerequisites

  • Maintenance Mode: The ESXi host should be placed in maintenance mode to prevent impact on live production workloads during the transition.
  • Physical Connectivity: Ensure the copper SFP modules and cables are installed. Confirm the physical switch ports are configured correctly (e.g., Link Up, correct VLANs, and Trunk port settings).
  • Hardware Verification: Confirm that the Copper SFP NIC is recognized by the ESXi host as a new PCI device.

Step 1: Prepare the Virtual Switch

  1. Log in to the vSphere Client.
  2. Navigate to the Virtual Switch or Distributed Virtual Switch (DVS) currently using the fiber uplinks.
  3. Add the new copper uplink(s) to the switch.
    • Note: Ensure the copper uplinks are set to Active, not Standby.

Step 2: Perform Logical Failover

Before physically disconnecting any cables, perform a logical shutdown of the fiber interface to ensure traffic migrates to the copper link.

This command will make changes to your system. Review it carefully before running.

esxcli network nic down -n vmnicX

(Replace vmnicX with the identifier of your fiber NIC)

Alternatively, you can administratively shut down the port on the physical switch side.

Step 3: Verify and Finalize

  1. Confirm that all virtual machine and management traffic has successfully failed over to the copper interface.
  2. Once connectivity is verified, you may physically disconnect the fiber cables.
  3. Remove the fiber vmnic from the Virtual Switch configuration.
  4. Exit Maintenance Mode and monitor connectivity.

Fallback Plan

If connectivity is lost during the migration, re-enable the fiber interface or physically reconnect the fiber cables to restore the original state.

Review this command before running it.

esxcli network nic up -n vmnicX
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