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How to include only vmware virtual disk for backup and exclude RDM

Level 4

Master/Media/Client : Win 2012 r2  and NBU version: 7.7.1.

Requirement is to backup only the virual disk and exclude the RDM from the backup. I tried to exclude data disk in policy but backup is failing with status code "156".

I have attached the configuration and  error logs. please check and help to sort out the issue.




Hi Manumohan,

I am guessing that you are trying to use a VMware policy to back up with machine with the RDM's?  I suspect your issue is due to the fact that NetBackup cannot back up the RDM by means of a VMware backup host.  This is a reason we moved our VM file server off RDM's.

Below are a couple of extracts from the NetBackup for VMware Administrator's Guide (Appendix D), and I've included the link to the full manual for your version:

You can use either of the following NetBackup configurations to back up disk arrays as RDMs:

  • Without Snapshot Client: Install a NetBackup client on the virtual machine. You can configure NetBackup to back up the virtual machine and any RDMs as if the client was installed on a physical host. Without Snapshot Client software on the virtual machine, the features of Snapshot Client are not available. (This configuration is not discussed in this NetBackup for VMware guide.)
  • With Snapshot Client: Install a NetBackup client and Snapshot Client software on the virtual machine.
  • Configure an alternate client backup.

Option 1 is the easiest - install a NetBackup client and in your Backup Selections, only choose the disks you want.  A bit slower than a straight VMware backup, but if you use things like Accelerator and dedupe it's not as bad as it could be.

Hope this helps,


Hi System_Team,

I am triying to use vmware policy to backup only the virtual disk of the VM and exclude RDM disk. Is there any way we can do this?

I believe Netbackuo will automatically do snapshot of  virtual disk and exclude RDM becaue it cannot snapshot.

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The disk selection is not your problem - it is the initial snapshot where VMware needs to make a snapshot of the entire VM. 

You will notice that snapshot option is greyed out in VMware management GUI.

This is why VMware policy type is not supported for VMs with RDM. 


correct on Vmware itself the snapshot option grey out.  I thought Netbackup API can do a snapshot by using the "exclude data disk" in vmware policy. Because OS is configured in the virtual disk (vmdk)

Thak you for the information Marianne.

I am stop trying NBU to take snapshot of only Virtual disk of the VM, when the VM is configured with virtual disk(vmdk) and RDM , it cannot be accomblished.