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How an ONTAP Cloud HA configuration provides non-disruptive operations

An ONTAP Cloud HA configuration ensures high availability of your data in case of software, storage, and networking failures.

HA components

An ONTAP Cloud HA configuration includes the following components:
  • Two ONTAP Cloud systems (nodes) whose data is synchronously mirrored between each other.
  • A mediator instance that provides a communication channel between the nodes to assist in storage takeover and giveback processes.
    Note: The mediator instance runs the Linux operating system on a t2.micro instance and uses one EBS magnetic disk that is approximately 8 GB.
  • Three floating IP addresses that can move between nodes, which enables storage failover for NFS and CIFS.
    Note: One floating IP address is for cluster management, one is for NFS/CIFS data on node 1, and one is for NFS/CIFS data on node 2. iSCSI data LIFs are created by default and use static IP addresses, rather than floating IP addresses.

The following image shows the relationship between these components:

Conceptual images showing the components in an ONTAP Cloud HA configuration: two ONTAP Cloud nodes, a mediator instance, and floating IP addresses.

Each of these components must be deployed properly in AWS.

AWS networking requirements for ONTAP Cloud HA configurations

Storage takeover and giveback

If a node goes down, the other node can serve data for its partner to provide continued data service. Clients can access the same data from the partner node because the data was synchronously mirrored to the partner.

When takeover occurs in a NAS configuration, the node's floating IP address that clients use to access data moves to the other node. For iSCSI, ONTAP Cloud uses multipath I/O (MPIO) and Asymmetric Logical Unit Access (ALUA) to manage path failover between the active-optimized and non-optimized paths.
Note: For information about which specific host configurations support ALUA, see the NetApp Interoperability Matrix Tool and the Host Utilities Installation and Setup Guide for your host operating system.

The following image depicts storage takeover in a NAS configuration. If node 2 goes down, the floating IP address for node 2 moves to node 1.

Conceptual image showing storage takeover in an ONTAP Cloud HA pair: the floating IP addresses from node 1 move to node 2.

After the node reboots, the partner must resync data before it can return the storage. The time that it takes to resync data depends on how much data was changed while the node was down.

RPO and RTO

An ONTAP Cloud HA configuration maintains high availability of your data as follows: