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  1. Home
  2. Veritas NetBackup™ for Hyper-V Administrator's Guide
  3. Troubleshooting
  4. NetBackup status codes related to Hyper-V
  5. Snapshot error encountered (status code 156)
Veritas NetBackup™ for Hyper-V Administrator's Guide

Snapshot error encountered (status code 156)

The following table describes the Hyper-V issues that relate to NetBackup status code 156.

Table: Possible causes of status code 156

Causes of status code 156

Description and recommended action

The virtual machine name is incorrectly specified in the NetBackup policy.

A mismatch may exist between the virtual machine names that are specified on the policy Clients tab and the actual names on the Hyper-V server. Check the actual names as listed in the Hyper-V Manager on the Hyper-V server.

The following are the recommended actions:

  • In the NetBackup policy, the virtual machines must be specified as fully qualified names.

  • In the NetBackup policy, the virtual machine name may have been entered incorrectly.

    If you browsed for the virtual machines on the Clients tab and selected names from the list, the list may be out of date. (The list is derived from a cache file.) Refresh the list by clicking on the icon next to the Last Update field.

Volumes on the virtual machine are almost full.

Volumes on the virtual machine do not have enough free space for the snapshot. Microsoft recommends that at least 10% of the virtual machine volume is available for the snapshot.

Recommended action: create more space on the volume.

The Hyper-V integration component is absent.

The Hyper-V integration component is not properly installed in the virtual machine.

Recommended action:

See The Hyper-V integration component is not installed.

The VSS framework in the virtual machine does not work properly

The following application error event may be written to the virtual machine during backup:

Event Type:     Error
Event Source:   VSS
Event Category: None
Event ID:       12302
Date:           1/8/2009
Time:           1:36:21 AM
User:           N/A
Computer:      ARTICTALEVM8

Description:

Volume Shadow Copy Service error: An internal inconsistency was
detected in trying to contact shadow copy service writers. 
Please check to see that the Event Service and Volume Shadow 
Copy Service are operating properly. 
For more information, see Help and Support Center at 
http://go.microsoft.com/fwlink/events.asp.

Recommended action: Run the vssadmin list writers command.

If no writer is listed in the output and a similar error is logged, refer to the following to resolve this issue:

http://support.microsoft.com/kb/940184

A CSV timeout occurred

The bpfis log contains the following:

VssNode::prepareCsvsForBackup: CSV TimeOut
expired, Not all required CSV available in required 
state.

One or more or the required cluster shared volumes (CSV) cannot be prepared in the specified timeout period. A current backup that started from another node needs one or more of the same CSVs.

Increase the Cluster shared volumes timeout period and rerun the backup, or try the backup at another time.

See Cluster shared volumes timeout (Hyper-V with VSS).

A local disk has been added to a VM that is on CSV

For a successful backup of a virtual machine on a CSV, the virtual machine must use CSV volumes only. If a local disk on the Hyper-V server (not a CSV volume) is added to the virtual machine, the backup fails.

Reconfigure the virtual machine to use CSV volumes only, and rerun the backup.

The Enable offline backup for non-VSS VMs option is disabled

The bpfis log contains the following:

VssNode::prepare Backup type of VM [<VM GUID>] 
will be OFFLINE and configuration parameter 
allowOfflineBackup] is not set. To backup 
this VM, set [allowOfflineBackup] configuration 
parameter.

NetBackup is not allowed to perform an offline backup of the virtual machine, because the Enable offline backup for non-VSS VMs option is disabled.

Enable the Enable offline backup for non-VSS VMs option.

See Enable offline backup of non-VSS VMs (Hyper-V with VSS).

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