1.2.4 Introduction to Oracle Cluster Health Advisor

Oracle Cluster Health Advisor continuously monitors cluster nodes and Oracle RAC databases for performance and availability issue precursors to provide early warning of problems before they become critical.

Oracle Cluster Health Advisor is integrated into Oracle Enterprise Manager Cloud Control (EMCC) Incident Manager.

Oracle Cluster Health Advisor does the following:

  • Detects node and database performance problems

  • Provides early-warning alerts and corrective action

  • Supports on-site calibration to improve sensitivity

In Oracle Database 12c release 2 (, Oracle Cluster Health Advisor supports the monitoring of two critical subsystems of Oracle Real Application Clusters (Oracle RAC): the database instance and the host system. Oracle Cluster Health Advisor determines and tracks the health status of the monitored system. It periodically samples a wide variety of key measurements from the monitored system.

Over a hundred database and cluster node problems have been modeled, and the specific operating system and Oracle Database metrics that indicate the development or existence of these problems have been identified. This information is used to construct a trained, calibrated model that is based on a normal operational period of the target system.

Oracle Cluster Health Advisor runs an analysis multiple times a minute. Oracle Cluster Health Advisor estimates an expected value of an observed input based on the default model. Oracle Cluster Health Advisor then performs anomaly detection for each input based on the difference between observed and expected values. If sufficient inputs associated with a specific problem are abnormal, then Oracle Cluster Health Advisor raises a warning and generates an immediate targeted diagnosis and corrective action.

Oracle Cluster Health Advisor models are conservative to prevent false warning notifications. However, the default configuration may not be sensitive enough for critical production systems. Therefore, Oracle Cluster Health Advisor provides an onsite model calibration capability to use actual production workload data to form the basis of its default setting and increase the accuracy and sensitivity of node and database models.

Oracle Cluster Health Advisor stores the analysis results, along with diagnosis information, corrective action, and metric evidence for later triage, in the Grid Infrastructure Management Repository (GIMR). Oracle Cluster Health Advisor also sends warning messages to Enterprise Manager Cloud Control using the Oracle Clusterware event notification protocol.

You can also use Oracle Cluster Health Advisor to diagnose and triage past problems. You specify the past dates through Oracle Enterprise Manager Cloud Control (EMCC) Incident Manager or through the command-line interface CHACTL. Manage the capability of Oracle Cluster Health Advisor to review past problems by configuring the retention setting for Oracle Cluster Health Advisor's tablespace in the Grid Infrastructure Management Repository (GIMR). The default retention period is 72 hours.