File restore from Hyper-V Guest machines running on a Clustered Host complete with an exception "Failed to mount one or more virtual disk images" when the Granular Recovery Technology (GRT) option is enabled in the backup job

Article:TECH170584  |  Created: 2011-09-28  |  Updated: 2014-03-19  |  Article URL http://www.symantec.com/docs/TECH170584
Article Type
Technical Solution


Subject

Issue



For backup of Hyper-V Virtual Machines (VM), the Microsoft Hyper-V VSS Writer is used to snap the volumes hosting the VHD files for the VM(s). During the GRT phase, these snapshots are mounted as a mount point on the host server to generate the catalog information for the backed up VM(s). By default Backup Exec creates the mount point on a volume that has the most free space. In some cases it is observed that the mount process fails if the volume being used to mount the snapshot is an ISCSI/SAN volume being managed by the Windows 2008 Failover Cluster.


Error



V-79-57344-38721 - Failed to mount one or more virtual disk images


 


Solution



Warning: Incorrect use of the Windows registry editor may prevent the operating system from functioning properly. Great care should be taken when making changes to a Windows registry. Registry modifications should only be carried-out by persons experienced in the use of the registry editor application. It is recommended that a complete backup of the registry and workstation be made prior to making any registry changes
 

 
1. Open the Registry Editor on the Hyper-V host server.
 
2. Browse to the hive: HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Backup Exec For Windows\Backup Exec\Engine\Virtual Disk Mounter
 
3. Create the following registry values as shown below:
 
     A. Value Name: Auto Discovery
 
         Type: DWORD
 
         Value: The value for this registry value can be set to 0 - normal processing, 1 - disable auto discovery, 2 - enable auto discovery
 
         To fix the above mentioned issue, this value needs to be set to 1.    
 
     B. Value:  Mount Point Root
 
         Type:  String
 
         Value:  The value for this registry value should point to the Path where the mount points should be stored. (For e.g. C:\Temp where C:\ is a local volume on the Hyper-V host server)
 
     C. Value:  Virt Space
 
         Type:  String
 
         Value: The value for this registry value should point to the Path where the virtualized files will reside. (For e.g. C:\Temp where C:\ is a local volume on the Hyper-V host server)
 
      D.  Value:  Delta Space
 
           Type:  String
 
           Value: The value for this registry value should point to the Path where the mount points should be stored. (For e.g. C:\Temp where C:\ is a local volume on the Hyper-V host server)
 

Supplemental Materials

SourceUMI
ValueV-79-57344-38721
Description
Failed to mount one or more virtual disk images.


Article URL http://www.symantec.com/docs/TECH170584


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