When setting up a new HPE StoreOnce appliance for a customer who is using NetBackup and requires the highest performance setup, the best backup target type to recommend is VTL (Virtual Tape Library). VTLs are optimized for high-performance environments, particularly when connected via Fibre Channel (FC), which the customer has in their local setup. VTLs provide the speed and reliability of disk-based storage while emulating the tape systems that many backup solutions, like NetBackup, are designed to work with. This setup will ensure the highest throughput and performance for backup operations over FC.
Reference:
HPE StoreOnce Overview
HPE VTL Solutions