ONTAP automatically assigns an HA policy of CFO or SFO to an aggregate that determines how storage failover operations (takeover and giveback) occur for the aggregate and its volumes.
HA policy is assigned to and required by each aggregate on the system. The two options, CFO (controller failover), and SFO (storage failover), determine the aggregate control sequence ONTAP uses during storage failover and giveback operations.
Although the terms CFO and SFO are sometimes used informally to refer to storage failover (takeover and giveback) operations, they actually represent the HA policy assigned to the aggregates. For example, the terms SFO aggregate or CFO aggregate simply refer to the aggregate's HA policy assignment.
Manually initiated takeover is optimized for performance by relocating SFO (non-root) aggregates serially to the partner prior to takeover. During the giveback process, aggregates are given back serially after the taken-over system boots and the management applications come online, enabling the node to receive its aggregates.
All other aggregates are given back serially after the taken-over system completes the boot process and the management applications come online, enabling the node to receive its aggregates.