High Availability Guide : Failure handling with High Availability Controller (HAC) : Secondary node fails
  
Secondary node fails
Scenario
The secondary node (node 2) fails.
The Primary database (in the PRIMARY ACTIVE state) on node 1 encounters connection failure to the Secondary database (in the SECONDARY ACTIVE state) on node 2.
Recovery
In the recovery from the Secondary node failure the Secondary server is restarted. The recovery proceeds automatically as follows:
1 Upon the connection failure, the Primary database on node 1 moves automatically to the PRIMARY UNCERTAIN state.
2 The HAC instance on the Primary database on node 1 concludes that the Secondary database on node 2 has failed.
3 The HAC instance on the Primary database on node 1 sets the Primary database to the PRIMARY ALONE state.
4 The Secondary node (node 2) is restarted.
5 The HAC instance on the Secondary database (node 2) is restarted.
6 The HAC instance on the Secondary database (node 2) concludes that the Secondary database is not running.
7 The HAC instance on the Secondary database (node 2) restarts the Secondary database and sets it to the SECONDARY ALONE state.
8 The HAC instance on the Primary database on node 1 initiates the process of connecting the Primary and Secondary database.
9 A catchup is made.
Optionally, the connection process includes a netcopy operation from the Primary database to the new Secondary database.
See also
Failure handling with High Availability Controller (HAC)