The following rules are available for Data guard monitoring:
DBO - DG Applied Gap
This alarm is invoked when the last applied log sequence# on the archive destination indicates a gap that exceeds a predefined threshold. Ensuring that the gap between the standby and the primary instances is kept as small as possible is important in order to prevent failover to the standby from causing large amount of data losses in a crisis situation.
DBO - DG Errors
This alarm fires when the total number of Data Guard errors exceeds a defined threshold. Errors generated from Dataguard status could indicate failure to synchronize the standby environment with the primary.
DBO - DG Received Gap
This alarm is invoked when the last received log sequence# on the archive destination indicates a gap that exceeds a predefined threshold. Ensuring that the gap between the standby and the primary instances is kept as small as possible is important in order to prevent failover to the standby from causing large amount of data losses in a crisis situation.
DBO - DG Redo Configuration
This alarm is invoked when the numbers of standby redo logs is equal or less than the number of online redo logs. Having a number of standby redo logs that is equal or less than the number of online redo logs increases the likelihood that the primary instance's log writer (LGWR) process will be blocked, because a standby redo log file cannot be allocated on the standby instance.