How storage works in an ONTAP Cloud HA pair

Unlike an ONTAP cluster, storage in an ONTAP Cloud HA pair is not shared between nodes. Instead, data is synchronously mirrored between the nodes so that the data is available in the event of failure.

Storage allocation

When you create a new volume and additional disks are required, Cloud Manager allocates the same number of disks to both nodes, creates a mirrored aggregate, and then creates the new volume. For example, if two disks are required for the volume, Cloud Manager allocates two disks per node for a total of four disks.

Storage configurations

You can use an ONTAP Cloud HA pair as an active-active configuration, in which both nodes serve data to clients, or as an active-passive configuration, in which the passive node responds to data requests only if it has taken over storage for the active node.

Note: You can set up an active-active configuration only when using Cloud Manager in the Storage System View.

Performance expectations for an ONTAP Cloud HA configuration

An ONTAP Cloud HA configuration synchronously replicates data between nodes, which consumes network bandwidth. As a result, you can expect the following performance in comparison to a single-node ONTAP Cloud configuration:

NetApp Technical Report 4383: Performance Characterization of ONTAP Cloud with Application Workloads

Client access to storage

Clients should access NFS and CIFS volumes by using the data IP address of the node on which the volume resides. If NAS clients access a volume by using the IP address of the partner node, traffic goes between both nodes, which reduces performance.

Important: If you move a volume between nodes in an HA pair, you should remount the volume by using the IP address of the other node. Otherwise, you can experience reduced performance. If clients support NFSv4 referrals or folder redirection for CIFS, you can enable those features on the ONTAP Cloud systems to avoid remounting the volume. For details, see ONTAP documentation.

You can easily identify the correct IP address from Cloud Manager.

The following image shows the Storage System View:

Screen shot: Shows the Mount Command which is available when you select an ONTAP Cloud volume.

The following image shows the Volume View:

Screen shot: Shows the menu options for a volume, which includes the Mount option.