Requirements for a NetBackup client inside the virtual machine
Although a NetBackup client is required on the Hyper-V server, it is not required in the virtual machine except in the following cases:
To back up the individual virtual drives that are inside the virtual machine. For example, the virtual drives that are on vhd (or vhdx) files as if they were on a physical host.
To back up the physical disks that the virtual machine accesses in a pass through configuration.
To back up disks in a pass through configuration by means of a VSS hardware snapshot provider, an alternate client configuration is required.
To back up databases or applications using NetBackup agents.