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  1. Home
  2. NetBackup™ for VMware Administrator's Guide
  3. Troubleshooting
  4. Snapshot error encountered (status code 156)
NetBackup™ for VMware Administrator's Guide

Snapshot error encountered (status code 156)

The following table describes the VMware issues that relate to NetBackup status code 156.

Table: Possible causes of status code 156

Causes of status code 156

Description and recommended action

NetBackup cannot obtain the volume ID of a drive

NetBackup may not be able to obtain the volume ID of a drive. In that case, none of the virtual machine drives are backed up. The backup fails with NetBackup status code 156.

The drive may be down.

A backup of the virtual machine is already active

You cannot run more than one backup per virtual machine at a time. If you start a second backup of the virtual machine while the first backup is active, the second job fails with a status 156.

Recommended action: Wait until the first job completes, then run the second one.

Cannot find virtual machine name

NetBackup cannot find the host name or VM display name of a virtual machine that is listed in the backup policy. The detailed status log may include the following error message:

Critical bpbrm (pid=<pid number>) from client <client name>:
FTL - snapshot creation failed, status 156.)

If the virtual machines do not have static IP addresses, you can configure NetBackup to identify virtual machines by their VM display names or UUIDs. Examples of the environments that do not use static IP addresses are clusters, and the networks that assign IP addresses dynamically.

Note that NetBackup may have been configured to identify virtual machines by their VM display names. In that case, make sure that the display names are unique and that they do not contain special characters.

See Primary VM identifier options (VMware).

The virtual machine is powered off

Through a vCenter server, NetBackup can back up the virtual machines that are turned off. You must provide credentials for NetBackup to access the vCenter server.

See Adding NetBackup credentials for VMware.

If NetBackup uses credentials for an ESX server instead of vCenter, it may not be able to identify a turned off virtual machine. Note the following:

  • If the policy uses VM host name or VM DNS name as the Primary VM identifier, NetBackup may not find the virtual machine. The backup fails.

  • If the policy uses VM display name or VM UUID as the Primary VM identifier, NetBackup can identify the virtual machine. The backup succeeds.

The virtual machine has one or more independent disks and is in a suspended state

If a virtual machine with independent disks is in a suspended state, snapshot jobs fail. Messages similar to the following appear in the job details log:

01/12/2015 17:11:37 - Critical bpbrm (pid=10144) from client 
<client name>: FTL - VMware error received: Cannot take a 
memory snapshot, since the virtual machine is configured with 
independent disks.

This issue results from a VMware limitation (SR#15583458301). More information is available in the following VMware article:

http://kb.vmware.com/kb/1007532

As a workaround, change the state of the virtual machine to powered on or powered off, and rerun the backup.

Note:

Data on independent disks cannot be captured with a snapshot. The rest of the virtual machine data is backed up.

The virtual machine's disk is in raw mode (RDM)

The RDM is ignored (not backed up) and any independent disk is recreated but empty.

See Configurations for backing up RDMs.

The attempt to create a snapshot exceeded the VMware timeout

If the attempt to create a snapshot of the virtual machine exceeds the VMware timeout of 10 seconds, the snapshot fails with NetBackup status 156. This timeout may occur if the virtual machine is configured with a large number of volumes. Note that the timeout may be encountered even if the Virtual machine quiesce option was disabled.

Do one of the following:

  • Reduce the number of volumes within the virtual machine.

  • Install a NetBackup client on the virtual machine and select another backup method for the policy (not the VMware snapshot method).

The virtual machine has no vmdk file assigned

The snapshot fails if the virtual machine has no vmdk file.

Virtual machines without vmdk files can occur in a vCenter Site Recovery Manager (SRM) environment. If a replicated virtual machine has never been active, it is in passive mode and may have no vmdk file(s).

You can enable the Ignore diskless VMs option on the VMware Advanced Attributes tab of the policy. If this option is enabled: NetBackup does not back up a replicated (passive) virtual machine in an SRM environment if that virtual machine has no vmdk files.

More information is available on the Ignore diskless VMs option.

See VMware - Advanced Attributes dialog.

The vmdk file has too many delta files

Whenever a VMware snapshot occurs, a delta.vmdk file is created for each vmdk. If 32 or more such delta files exist for a single vmdk file, a NetBackup backup of that VM may fail (status 156). The NetBackup Activity Monitor job details contain messages similar to the following:

02/06/2015 10:33:17 - Critical bpbrm (pid=15799) from 
client fl5vm1_2012: FTL - vSphere_freeze: Unable to proceed with 
snapshot creation, too many existing delta files(44).
02/06/2015 10:33:17 - Critical bpbrm (pid=15799) from client
fl5vm1_2012: FTL - VMware_freeze: VIXAPI freeze (VMware snapshot)
failed with 25: SYM_VMC_FAILED_TO_CREATE_SNAPSHOT
02/06/2015 10:33:17 - Critical bpbrm (pid=15799) from client
fl5vm1_2012: FTL - vfm_freeze: method: VMware_v2, type: FIM,
function: VMware_v2_freeze

To back up the VM, do the following:

  1. Consolidate the VM's snapshots.

    In the VMware interface, right-click on the VM and select Snapshot > Consolidate. For more information, see your VMware documentation.

  2. Verify that each of the VM's vmdk files now has fewer than 32 delta files.

    If the snapshot consolidation was not successful, see the following VMware article for further assistance:

    Committing snapshosts in vSphere

  3. Rerun the NetBackup backup.

VMware snapshot quiesce operation failed

If the NetBackup policy is enabled for virtual machine quiesce (the default), the VMware snapshot operation in vSphere initiates a quiesce of the virtual machine. If snapshot quiesce fails, the NetBackup job fails with status 156.

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