Exam NS0-162 topic 1 question 48 discussion

Answer appears to be C, the question refers to use Adaptive QOS with the 'default' policy, which is "used space policy". A used space policy (the default) maintains the IOPS/TB|GB ratio according to the amount of actual data stored before storage efficiencies. If the ratio is 100 IOPS/GB, a 150 GB volume that has 100 GB of data stored would have a throughput ceiling of 10,000 IOPS. As the amount of used space changes, adaptive QoS adjusts the throughput ceiling according to the ratio. https://docs.netapp.com/us-en/ontap/performance-admin/guarantee-throughput-qos-task.html#about-adaptive-qos

A seems to be right. As Used space is a logical space. Resize is more appropriate: https://kb.netapp.com/onprem/ontap/Performance/What_is_Adaptive_QoS_and_how_does_it_work

Agree with NCDA. The default policy (used space) changes based on used space

C, the default policy is used space

Answer is A Adaptive QoS Policy Groups – Allocated Space When you use allocated space, an allocated space policy maintains the IOPS to TB/GB ratio, according to the nominal size of the storage object. For example, if the ratio is 100 IOPS/GB, a 300 GB volume will have a throughput ceiling of 30,000 IOPS. If the volume is resized to 500 GB, adaptive QoS adjusts the throughput ceiling to 50,000 IOPS. You can see here that it doesn't care how much data is actually in the volume. It's applied based on the size of the volume is. With adaptive QoS working here, as the size of the volume increased, that volume was given more throughput.

If the TB/GB ratio to IOPS is 100 IOPS/GB, a 300GB volume will have a throughput ceiling of 30,000 IOPS. If the volume is resized to 500GB, adaptive QoS adjusts the throughput ceiling to 50,000 IOPS.

A is correct. https://kb.netapp.com/Advice_and_Troubleshooting/Data_Storage_Software/ONTAP_OS/What_is_Adaptive_QoS_and_how_does_it_work