You must install and configure an Oracle database instance to house the Always-On Monitoring repository. Because you must create the schema for the repository separately, it is critical to have an idea of the space that needs to be allocated to the schema, and how the space is broken down.

Because the purpose of Always-On Monitoring is to continuously monitor and send notifications when Enterprise Manager is down, the Always-On Monitoring Repository database should be installed as a separate instance of Oracle with the Always-On Monitoring Schema on another machine so that Always-On Monitoring continues to run when the Enterprise Manager Repository is either being upgraded or unexpectedly goes down.

Like the Enterprise Manager Repository, the Always-On Monitoring Repository needs to be installed on an Oracle database. The database version supported depends on the Always-On Monitoring version as shown in the following table: