4.1 Understanding Cluster Health Monitor Services

Cluster Health Monitor uses system monitor (osysmond) and cluster logger (ologgerd) services to collect diagnostic data.

About the System Monitor Service

The system monitor service (osysmond) is a real-time monitoring and operating system metric collection service that runs on each cluster node. The system monitor service is managed as a High Availability Services (HAS) resource. The system monitor service forwards the collected metrics to the cluster logger service, ologgerd. The cluster logger service stores the data in the Oracle Grid Infrastructure Management Repository database.

In addition, osysmond persists the collected operating system metrics under a directory in ORACLE_BASE.

Metric Repository is auto-managed on the local filesystem. You can change the location and size of the repository.

• Nodeview samples are continuously written to the repository (JSON record)
• Historical data is auto-archived into hourly zip files
• Archived files are automatically purged once the default retention limit is reached (default: 200 MB)

About the Cluster Logger Service

The cluster logger service (ologgerd) is responsible for preserving the data collected by the system monitor service (osysmond) in the Oracle Grid Infrastructure Management Repository database. In a cluster, there is one cluster logger service (ologgerd) per 32 nodes. More logger services are spawned for every additional 32 nodes. The additional nodes can be a sum of Hub and Leaf Nodes. Oracle Clusterware relocates and starts the service on a different node, if:

• The logger service fails and is not able to come up after a fixed number of retries

• The node where the cluster logger service is running, is down

Support for Deploying Grid Infrastructure Management Repository (GIMR) into a Separate Oracle Home

Starting with Oracle Grid Infrastructure 20c, you must configure the Grid Infrastructure Management Repository (GIMR) in a separate Oracle home, instead of in the Grid home. This option is available when you configure GIMR during a fresh Oracle Grid Infrastructure installation or you add a GIMR to an existing deployment. It is mandatory to configure GIMR in a separate Oracle home when you upgrade Oracle Grid infrastructure with an existing GIMR deployed in it.

A separate Oracle home for the GIMR ensures faster rolling upgrades, less errors, and fewer rollback situations. The Oracle Grid Infrastructure installation owner user must own the GIMR home.

For more information, see Installing Grid Infrastructure Management Repository

Remote GIMR Support for Oracle Standalone Clusters

The remote Grid Infrastructure Management Repository (GIMR) feature for Oracle Standalone Cluster enables you to use a centralized GIMR. This feature does not require local cluster resources to host the GIMR.

The remote GIMR feature provides access to a persistent data store that significantly enhances the proactive diagnostic functionality of Cluster Health Monitor, Cluster Health Advisor, and Autonomous Health Framework clients. The remote GIMR feature saves cost by freeing up local resources and licensed database server resources.

For more information, see Creating GIMR Credentials File for Oracle Standalone Clusters With Remote GIMR