User must have deployed NetBackupon Azure with Azure disks as its storage class.

While upgrading to latest NetBackup, data migration would happen only if existing storage class has been changed. The existing catalog data of primary server will be migrated (copied) from Azure disks to Azure premium files. Also new data volume would be created on Azure disks for NetBackup database. If storageClassName is changed for log, migration from azure disk to azure disk will trigger for logs.

Fresh NetBackup deployment: If user is deploying NetBackup for the first time, then Azure premium files will be used for primary server's catalog and Azure disks will be used for log and data volume for any backup and restore operation.