Unable to migrate powered off VM or Templates using type "Change both compute resource and storage" between ESX clusters

Products

• VMware vSphere ESXi

Issue/Introduction

• Compute only migrations (hot and cold) succeeds.
• Task for powered off VM gets stuck for a long time before timing out at around 22% progress.
• Cloning of VMs or Templates fails.
• Expecting traffic to travel over "vMotion" vmkernel adapter network.

 

Log events showing Network File Copy (NFC) failed task as timed out.

• VCSA /var/log/vmware/vpxd/vpxd.log
  
  

  2025-12-22T12:47:23.273-06:00 error vpxd[07391] [Originator@6876 sub=VmProv opID=###-###-###] Failed to track task vim.Task:haTask--nfc.NfcManager.copy-26343178 on host vim.

  HostSystem:host-##: Fault cause: vim.fault.Timedout
  
  

  2025-12-22T12:47:23.274-06:00 error vpxd[07391] [Originator@6876 sub=VmProv opID=###-###-###] Aborting task tracking since task vim.Task:haTask--nfc.NfcManager.copy-26343178

  failed
  
  

  2025-12-22T12:47:23.275-06:00 error vpxd[07391] [Originator@6876 sub=VmProv opID=###-###-###] Get exception while executing action vpx.vmprov.CopyVmFiles:

  --> (vim.fault.Timedout) {

  --> msg = "",

Cause

ESX hosts in the cluster may have their "Management" vmkernel adapter configured with incorrect network subnet mask. (e.g., CIDR of 10.0.0.0/23 but using subnet mask of 255.255.255.0 [/24]).

• Note: When a VM is powered off it uses the "Management" vmk as default. When a VM is powered on it uses the "vMotion" vmk by default. If "Provision" is enabled the traffic will traverse over the specified vmk. See KB 'A "Provisioning" network is not configured on the source or destination host. This can lead to lower network copy throughput.' for more details on the "Provisioning" feature for vmkernel adapters.

Resolution

For each ESX host update the Management vmkernel adapter to use the proper subnet mask.

• For the example of using CIDR 10.0.0.0/23, the subnet should be 255.255.254.0, not 255.255.255.0.

Additional Information

To test network communications between ESX hosts you could do the following.

• SSH to the source ESX host and run below command to test communication to target ESX host on the vmk being used for the migration. The port we need to test is 902 for NFC (Network File Copy - for storage migrations).
  
  nc -vz <Destination_Host_IP> 902 (make sure to use the IP of the “Management” vmk or the one specified if “Provision” is enabled)
  
  Successful Output example: “Connection to <IP> 902 port [tcp/*] succeeded!”

• Also run the command from the target to the source host to confirm traffic is working both ways between the hosts.

 

Helpful articles:

• vSphere 8 - Host Configuration for vSphere vMotion
• vSphere Virtual Machines Migration