Data Domain: How to Test VTL Functionality in NetBackup

Summary: This article describes NetBackup command‑line tools that are used to validate Virtual Tape Library (VTL) functionality during initial configuration or when troubleshooting potential device issues. These commands allow testing outside of the NetBackup UI to confirm device visibility, robot behavior, drive loading, and tape operations. ...

This article applies to This article does not apply to This article is not tied to any specific product. Not all product versions are identified in this article.
Check out other resources

Instructions

During initial VTL configuration on a new host, or when you suspect device misconfiguration, backup failures, or loss of volume access, VTL functionality may have to be tested independently of the NetBackup UI.

NetBackup provides CLI tools that allow direct validation of device visibility and robotic operations, even when the UI configuration is incomplete or incorrect; provided the VTL devices are visible to the operating system and accessible through the NetBackup pass‑through driver (on operating systems that require it).

These commands should be used only for initial setup or troubleshooting.
They must not be used while NetBackup is actively managing devices or running backup/restore jobs.

If using robtest on a media server that manages multiple libraries, take extreme care when selecting the robot number. Choosing the wrong robot may interfere with other connected libraries.

Verify Device Visibility.

Use the NetBackup scan utility (or sgscan on Solaris) to show available devices: 
Commands
Windows:
C:\Program Files\Veritas\Volmgr\bin\scan

UNIX/Linux:
/usr/openv/volmgr/bin/scan
 
The output should provide a list of devices, along with their Serial Numbers. 

You can match the devices reported with the devices configured on DD VTL and confirm that they are visible. 

If the scan command can see the changer exported by DD VTL, you can proceed with the robtest command to check basic device functionalities. 

Test Robot and Drive Operations Using robtest

NetBackup’s robtest utility directly manages robotic operations and can be used to confirm:
  • Robot control
  • Drive mapping
  • Slot inventory
  • Volume movement
Commands
Windows:
C:\Program Files\Veritas\Volmgr\bin\robtest

UNIX/Linux:
/usr/openv/volmgr/bin/robtest
 
The robtest startup output lists robots in the form: 
TLD(#)

Verify the correct robot number in the NetBackup UI before choosing one.

Incorrect selection may disrupt other active libraries.
 
After finding the correct robot, select it and you have access to an interactive command prompt.
You can use the following commands to run your tests:
  • List drives and check if they are empty or loaded
    • s d (means "show drives" It returns the status of all drives)
  • List slots and check volume barcodes
    • s s (means "show slots" It returns the status of all slots)
  • Mount a volume into a drive
    • m s# d# (means "move from slot# to drive#;" as an example: "m s1 d1")
  • Unload a volume from a drive, making it available for moving back to slot (this is not required if the VTL option "auto-offline" is enabled)​​​​​​​
    • unload d# (means "unload drive#")
  • Move a volume back to the slot​​​​​​​
    • m d# s#  (means "move from drive# to slot#")

Additional OS‑Level Drive Testing

On UNIX/Linux hosts, you can further validate drive behavior using: 
mt status
To check drive state.

For I/O testing on a blank tape, you may use commands such as: 
tar
dd

Important robtest Warning

As documented by Veritas:

Veritas warning bout utility interfering with robotic operations and preventing any mounts or dismounts

Additional Information

Device discovery from CLI:
How to do device discovery from the command line for NetBackup device configuration (External Link)

Robtest SCSI functionality tests:
Robtest commands that can be used to test the SCSI functionality of a robot (External Link)

Device verification with robtest:
How to verify device configuration using robtest (External Link)

Affected Products

Data Domain, Data Domain Virtual Tape Library
Article Properties
Article Number: 000010309
Article Type: How To
Last Modified: 27 Mar 2026
Version:  5
Find answers to your questions from other Dell users
Support Services
Check if your device is covered by Support Services.