NVP-vProxy: VMs are not getting all disks backed up (Skipping disk 2002 "Hard disk 3" not explicitly referenced in the backup request.)

The NetWorker VMware Protection integration is configured with the vProxy Appliance. The backup skips certain disks on specific Virtual Machines (VM). The backup workflow log shows:

YYYY/MM/DD HH:MM:SS NOTICE: [@(#) Build number: 189] Skipping disk 2002 "Hard disk 3" not explicitly referenced in the backup request.
YYYY/MM/DD HH:MM:SS NOTICE: [@(#) Build number: 189] Skipping disk 2003 "Hard disk 4" not explicitly referenced in the backup request.
YYYY/MM/DD HH:MM:SS NOTICE: [@(#) Build number: 189] Skipping disk 2004 "Hard disk 5" not explicitly referenced in the backup request.
YYYY/MM/DD HH:MM:SS TRACE:  [@(#) Build number: 189] Backing up 2 virtual disks...

The VMware snapshot creation does not allow snapshots of "Independent Persistent Disks," so the vProxy backup workflow skips the disks. The vProxy backup workflow requires a snapshot of the virtual disk to perform the VM backup.

The Independent disks support information is documented in the "NetWorker VMware Protection Solution best practices with the vProxy Appliance" of the Dell Technologies NetWorker VMware Integration Guide:

When you plan the backups, ensure that NetWorker VMware Protection supports the disk types that you use in the environment. Currently, NetWorker VMware Protection does not support the following disk types:

• Independent (persistent and non-persistent)
• RDM Independent - Virtual Compatibility Mode
• RDM Physical Compatibility Mode