Virtual machine clone and cold migration fails with the error: A general system error occurred: Configuration information is inaccessible

Products

• VMware vCenter Server

Issue/Introduction

Symptoms:

• Storage operations, including cold migration, Storage vMotion, and cloning of a virtual machine fails when using vCenter Server 5.0 and managing ESXi/ESX 4.x hosts
  
  Note: The above storage operations failing, has been reported to occur at different stages, for example: 99%, 85%.
  
  
• You see the error:
  
  A general system error occurred: Configuration information is inaccessible.

Cause

This article describes a specific issue. If you experience all of the above symptoms, consult the sections below. If you experience some but not all of these symptoms, your issue is not related to this article. Search the Knowledge Base for your symptoms or Open a Support Request.

Possible scenarios to consider:

• Cloning an IDE disk virtual machine to the same ESXi/ESX 4.x host with Changed Block Tracking (CBT) enabled fails.
• Cloning an IDE disk virtual machine from ESXi/ESX 4.x host to ESXi 5.0 host with CBT enabled is successful.
• Cloning a SCSI disk virtual machine from ESXi/ESX 4.x host to another ESXi/ESX 4.x host is successful.

This article only applies if all of these statements are true:

• The virtual machine in question uses IDE disks and Changed Block Tracking (also referred to as CTK)
• vCenter Server version is 5.0 or higher
• The virtual machine is on an ESXi/ESX 4.x host
  

Resolution

This is a known issue with vCenter Server 5.x in combination with ESXi/ESX 4.x and virtual machines using IDE disks with CTK enabled.

This issue is resolved in:

• vCenter Server 5.0 Update 2
  
  For more information, see the vCenter Server 5.0 Update 2 Release Notes.
  
  
• vCenter Server 5.1 Update 1
  
  For more information, see the vCenter Server 5.1 Update 1 Release Notes.

To download vCenter Server 5.0 Update 2 or vCenter Server 5.1 Update 1, see the VMware Download Center.

If you are unable to upgrade your ESXi/ESX hosts to 5.0 Update 2 or later, you can use these steps to disable changed block tracking.

To disable CBT in the configuration (.vmx) file:

1. Power off the virtual machine.
2. Right-click the virtual machine and click Edit Settings.
3. Click the Options tab, then click General.
4. Click Configuration Parameters.
5. Locate the values below for the IDE disk, and set the values to FALSE.
   
   For example:
   
   ide0:0.ctkEnabled = "TRUE"
   ctkEnabled = "TRUE"
   
   
6. Click OK then OK again.
7. Power on the virtual machine and retry the clone operation.

Note: If the issue persists, power off the virtual machine and remove it from the inventory, then add the virtual machine back into inventory for the change to take effect.

Additional Information

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For more information regarding Changed Block Tracking (CBT) on virtual machines, see Changed Block Tracking (CBT) on virtual machines (1020128).
Changed Block Tracking (CBT) on virtual machines

Impact/Risks:
Disabling CBT will delete Epochs and will impact backups of virtual machines when using VDR.