When your NetScaler appliances are running in a High Availability (HA) pair you should be aware when failovers occur, as this indicates an issue on one or both of the appliances, which you need to solve before both the appliances have the same issue.
In the case the latter happens, or is already the case, the appliances will fail over continuously, which is known as HA failover ‘flip-flopping’. Especially this scenario is important to be aware of, since it results in performance degradation and impacts user experience directly.
MetrixInsight for NetScaler monitors if failovers occur and alarms you whenever this happens.