HA (High Availability)

HA Status provides the status of the HA relationships for OAM and MP servers, which are configured to run as either active-standby server pairs or individual servers. The internal status fields are used to map to a Derived HA Status. The Derived HA Status is displayed as the HA Status.

The Availability state of a server is used by HA to determine when a switchover is necessary. Availability is ranked with a score. A lower score is better and means the server is in better health. The decision to switchover is based on this score. The switchover only occurs if a Standby server is deemed to be in better health (has a lower score) than an Active server. If the Standby's score is equal to or higher than the Active's score, then a switchover does not occur. In the HA Status screen, the server taking over shows its HA Status going to Active and HA Role going to Providing Service. The mate shows its unhealthier status.

Availability states are driven from conditions or events which have occurred on a server. As events and conditions change on a server, its Availability status can change. Depending on the set of conditions on an Active-Standby server pair, a switchover may occur.