You can monitor QoS performance with predefined analytics reports, which can be found under Predefined Analytics in the Analytics -> Analytics page in the VAST Web UI:
Click the User report category and run one of the following reports to view QoS analytics per user:
User Bandwidth
User IOPS
User Latency
User QoS Wait Time (the amount of time the user's request was waiting for processing due to applicable QoS policies)
Click the View report category and run QoS average wait time report to view QoS average wait time per view.