Troubleshooting migration compatibility warning: Device uses backing which is not accessible

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• When performing a vMotion migration the following compatibility warning is displayed:
  
  Unable to migrate from <source server> to <destination server>: Device '<device>' uses backing '<device>', which is not accessible .

Environment

VMware VirtualCenter 2.0.x
VMware VirtualCenter 2.5.x

Resolution

Overview

This unable to migrate warning message indicates that the virtual machine has a device that is disconnected and pointing to an image that is not accessible on the destination host.

The possible devices that can show this warning are:

• CD ROM Drive
• Floppy Drive

This warning can be safely ignored and only appears if you are using an image file (ISO, FLP, etc.) and not a physical device.

Workaround

To workaround the issue, perform one of the following actions:

• Ensure that the image being used in the device is accessible from all ESX Servers by storing the files on a datastore that is shared between all ESX Servers and participate in vMotion of the virtual machine.
  
  
• Edit the settings of the virtual machine and configure the drive to use the client device before performing a migration.