Amazon FSx for NetApp ONTAP (FSxN) and Azure NetApp Files (ANF) are first-party, fully managed file storage services delivered natively on AWS and Microsoft Azure, respectively. Both solutions are billed on a metered, pay-as-you-go basis, charging for consumed resources like storage capacity, performance tiers, and data protection features. They are designed as cloud-native services to provide high-performance, scalable NAS (NFS and SMB) volumes without requiring the customer to manage the underlying storage infrastructure, perfectly fitting the description of a metered, cloud-native file storage solution.

A. NetApp AFF systems: These are on-premises, all-flash hardware appliances purchased as a capital expense, not a metered, cloud-native service.

B. NetApp ONTAP Select software: This is a software-defined storage solution deployed on commodity hardware, typically in a private cloud or on-premises data center, and is not a metered public cloud service.

C. NetApp Cloud Volumes ONTAP: While this is a metered cloud solution, it is a customer-managed software instance running on IaaS, not a fully managed service like ANF and FSxN.

1. Amazon Web Services Documentation: On the pricing model for FSx for NetApp ONTAP, it states, "With Amazon FSx for NetApp ONTAP, you pay only for the resources you use with no minimum fees or set-up charges." This confirms its metered nature.

Source: AWS, "Amazon FSx for NetApp ONTAP pricing," Section: "Pay only for what you use."

2. Microsoft Azure Documentation: The pricing overview for Azure NetApp Files explains its billing model: "Billing for Azure NetApp Files is based on provisioned storage capacity... The cost is based on a per-GiB-per-hour basis." This is a clear example of metered storage.

Source: Microsoft, "Pricing - Azure NetApp Files," Main pricing description.

3. NetApp Official Product Page: NetApp's documentation distinguishes between its cloud offerings. It explicitly categorizes Amazon FSx for NetApp ONTAP and Azure NetApp Files as "Fully managed services," while Cloud Volumes ONTAP is described as "Customer-managed software." This supports the grouping of FSxN and ANF as the intended answer for fully managed, metered solutions.

Source: NetApp, "NetApp Cloud Storage," Product category descriptions.