Clusterware Stack Management and Troubleshooting - Expert Oracle RAC 12c - page 61

The System Monitor Service process ( osysmon ) runs on every node of the cluster. The System Monitor Service
monitors the OS and cluster resource-related degradation and failure and collects the real-time OS metric data and
sends these data to the cluster logger service.
Instead of running on every cluster node as in Oracle Clusterware 11gR2, there is only one cluster logger service
per every 32 nodes in Oracle Clusterware 12cR1. For high availability, this service will be restarted in another node if
this service fails.
On the node that runs both osysmon and ologgerd :
grid@knewracn1]$ ps -ef | grep -E 'osysmond|ologgerd' | grep -v grep
root 4408 1 3 Feb19 ? 08:40:32 /u01/app/12.1.0/grid/bin/osysmond.bin
root 4506 1 1 Feb19 ? 02:43:25 /u01/app/12.1.0/grid/bin/ologgerd -M -d
/u01/app/12.1.0/grid/crf/db/knewracn1
On other nodes that run only osysmon :
[grid@knewracn2 product]$ ps -ef | grep -E 'osysmond|ologgerd' | grep -v grep
root 7995 1 1 Feb19 ? 03:26:27 /u01/app/12.1.0/grid/bin/osysmond.bin
In Oracle Clusterware 12cR1, all the metrics data that the cluster logger service receives are stored in the central
Oracle Grid Infrastructure Management Repository (the CHM repository), which is a new feature in 12c Clusterware.
The repository is configured during the installation or upgrade to Oracle Clusterware by selecting the “Configure Grid
Infrastructure Management Repository” option in Oracle Universal Installer (OUI), as shown in Figure 2-6 .
Figure 2-6. Configure Grid Infrasturecture Management Repository in OUI
This repository is an Oracle database. Only one node runs this repository in a cluster. If the cluster is a Flex
Cluster, this node must be a hub node. Chapter 4 will discuss the architecture of Oracle Flex Clusters and different
types of cluster nodes in a Flex Cluster.