In a Cloud Volumes ONTAP (CVO) High-Availability (HA) pair deployed across multiple AWS Availability Zones, a floating IP address is used for NAS (NFS/SMB) data LIFs. This IP address is not tied to a specific CVO instance but rather to the HA pair's logical service. During a failover event, Cloud Manager orchestrates the failover by automatically updating the AWS VPC route tables. The route for the floating IP is changed to point to the Elastic Network Interface (ENI) of the node that is taking over, ensuring that NAS clients can continue to access data using the same IP address without disruption.

A. Dedicated tenancy is an AWS EC2 hosting option that provides physically isolated hardware; it does not provide a network failover mechanism.

C. Subnet CIDR reservations are used to reserve IP ranges within a VPC subnet for manual assignment, which is a static configuration, not a dynamic failover solution.

D. MPIO/ALUA (Multipath I/O / Asymmetric Logical Unit Access) is a technology used to provide path redundancy and load balancing for SAN protocols (iSCSI, FC), not for NAS protocols.

1. NetApp Cloud Volumes ONTAP Documentation, "Networking requirements for HA pairs in multiple AZs": "For NAS access, you need to provide one or more floating IP addresses. A floating IP address can move between the nodes in the HA pair. During normal operation, the floating IP address is assigned to a network interface on the primary node. If a failure occurs, the floating IP address is reassigned to a network interface on the standby node."

2. NetApp Cloud Volumes ONTAP Documentation, "How failover and giveback works for HA pairs in multiple AZs": "When a failover or giveback occurs, Cloud Manager modifies AWS route tables so that client traffic is routed to the other Cloud Volumes ONTAP instance. For example, if node 1 fails, Cloud Manager modifies the route tables to route traffic to node 2." This describes the implementation of the floating IP address.