High availability creates a replica for the vRealize Operations primary node and protects the analytics cluster against the loss of a node.

Cluster Management
Clusters consist of a primary node, a primary replica node, data nodes, and remote collector nodes.

Enabling High Availability within vRealize Operations is not a disaster recovery solution. When you enable High Availability, information is stored (duplicated) in two different analytics nodes within the cluster. This doubles the system's compute and capacity requirements. If either the primary node or the primary replica node is permanently lost, then you must disable, and then re-enable High Availability to reassign the primary replica role to an existing node. This process, which includes a hidden cluster rebalance, can take a long time.

Analytics Nodes

Analytics nodes consist of a primary node, primary replica node, and data nodes.

When you enable High Availability, you protect vRealize Operations from data loss when only a single node is lost. If two or more nodes are lost, there may be permanent data loss. Deploy each analytics node to separate hosts to reduce the chance of data loss if a host fails. You can use DRS anti-affinity rules to ensure that the vRealize Operations nodes remain on separate hosts.

Collector Group
In vRealize Operations, you can create a collector group. A collector group is a collection of nodes ( Cloud Proxy, analytics nodes and remote collectors). You can assign adapters to a collector group, rather than assigning an adapter to a single node.
Note: A collector group must contain the same type of nodes. You cannot mix Cloud Proxy, analytics nodes and remote collectors in a collector group.
If the node running the adapter fails, the adapter is automatically moved to another node in the collector group.
Assign all normal adapters to collector groups, and not to individual nodes. Hybrid adapters require a two-way communication between the adapter and the monitored endpoint.

For more information about adapters, see Adapter and Management Packs Considerations.