Azure NetApp Files supports three service levels: Ultra storage, Premium storage, and Standard storage. Each of these service levels are designed for different performance needs:

These service levels are an attribute of a capacity pool. You need to set up a capacity pool for each service level that you want to use with your Kubernetes clusters. Learn how to set up capacity pools.

Astra Control Service uses these service levels as storage classes for your persistent volumes. When you add Kubernetes clusters to Astra Control Service, you're prompted to choose either Ultra, Premium, or Standard as the default storage class. The names of the storage classes are netapp-anf-perf-ultra, netapp-anf-perf-premium, and netapp-anf-perf-standard.

Learn more about these service levels in the Azure NetApp Files docs.

As described above, the throughput for each service level is per 1 TiB of provisioned capacity. That means larger volumes provide better performance. So you should take both capacity and performance needs into consideration when provisioning volumes.

Astra Control Service provisions persistent volumes using a minimum volume size of 100 GiB, even if the PVC asks for a smaller volume size. For example, if the PVC in a Helm chart asks for 6 GiB, Astra Control Service automatically provisions a 100 GiB volume.

If you back up an application that resides on Azure NetApp Files storage, Astra Control Service automatically temporarily expands the capacity pool. After the backup is complete, Astra Control Service shrinks the capacity pool to its previous size. Depending on your Azure subscription, you might incur storage charges when this happens. You can see a history of capacity pool resize events in the Activity page event log.

If the capacity pool exceeds the maximum size allowed by the Azure subscription during the resize operation, the backup operation fails, and a warning is triggered from the Azure API.