If your cluster consists of a single HA pair

Cluster high availability (HA) is activated automatically when you enable storage failover on clusters that consist of two nodes, and you should be aware that automatic giveback is enabled by default. On clusters that consist of more than two nodes, automatic giveback is disabled by default, and cluster HA is disabled automatically.

A cluster with only two nodes presents unique challenges in maintaining a quorum, the state in which a majority of nodes in the cluster have good connectivity. In a two-node cluster, neither node holds epsilon, the value that designates one of the nodes as the master. Epsilon is required in clusters with more than two nodes. Instead, both nodes are polled continuously to ensure that if takeover occurs, the node that is still up and running has full read-write access to data as well as access to logical interfaces and management functions. This continuous polling function is referred to as cluster high availability or cluster HA.

Cluster HA is different and separate from the high availability provided by HA pairs and the storage failover commands. While crucial to full functional operation of the cluster after a failover, cluster HA does not provide the failover capability of the storage failover functionality.