Updated March 8, 2017
The database instance availability alert is configured for a short interval such as 1 minute. When the instance goes down, the alert is not firing or does not trigger for a while after the instance is not connected.
All DPA versions
This alert had a history of alerting and giving a false positive. It is based on us simply connecting to the instance but a few things have to be true for it to fire.
The monitor has to be on but, connection to the server is not working.
Then we also have a tolerance in the code where we sample every 90 seconds by default and if we have 3 attempts that fail 90 seconds apart we alert.
This alert is configurable. You can set the interval that we pull as well as the number of fails for a pull.
Go to Options > Administration tab > Advanced Options > DB instance Options tab > select the instance you want to change from the drop down menu.
ALERT_CONNECTION_INTERVAL - default is 90
ALERT_CONNECTION_ATTEMPTS - default is 3
Tune these settings to find the level of alert that works for your environment. This about finding the balance between false alerts and not alerting soon enough.