Node additions in unified ONTAP don't require any extra steps, but to provide balanced performance across all nodes (including the new nodes), volumes would need to be moved to the new nodes. This requires upfront analysis of the existing volumes and their workloads, decisions about which volumes to move, and then the actual volume moves taking place, which, again, would require a copy of that data across the backend cluster network.

Node removals in unified ONTAP would require a manual evacuation of existing volumes on the node, which means you must identify which nodes can host which volumes to maintain even performance, and you must have enough free capacity to provide a place for those volumes to move. If free capacity is a challenge, additional volume moves may be needed to shuffle workloads around a bit in the cluster. Node removals also HA pair removals, so the work involved is doubled. Because nodes own disks, an entire disk reinitialization would also be required for those nodes. Each of these things add time and effort to what should be a relatively simple task.

Node additions in NetApp AFX will not require the same up-front volume analysis, nor will it require administrative intervention to ensure that each node has an even balance of volumes. Instead, ONTAP automatically balances volume counts across newly added nodes to maintain relatively even performance profiles. ONTAP automatically will move volumes across nodes without copying anything, reducing the time, capacity, and effort required for adding nodes to a cluster.

Node removals in NetApp AFX also don't require much – if any – manual intervention. When a node is tagged for removal, ONTAP automatically moves volumes across nodes (again, without copying) to evacuate the nodes being removed. And because there are no disks owned by the nodes, there is no need to reinitialize disks after removing nodes. This makes nodes in AFX modular in nature and easy to scale up or down.