RAC instances status
Job details
| Name: |
RAC instances status |
| Platform: |
Oracle |
| Category: |
Cluster and Replication |
| Description: |
Reacts if one or more RAC instances are not available. |
| Long description: |
Reacts if one or more RAC instances are not available. |
| Version: |
1.0 |
| Default schedule: |
* * * * |
| Requires engine install: |
Yes |
| Compatibility tag: |
.[type=‘instance’ & databasetype=‘oracle’]/.[hasengine=‘YES’ & iscluster = ‘1′] |
Parameters
| Name |
Default value |
Description |
| ignore instances |
|
Instance names excluded from being checked (comma separated) |
| return status when instance is NOT OPEN |
2 |
Return status value (ALARM – 2, WARNING – 1, or OK – 0) when instances do not have status “OPEN“. |
| return status when instance is MISSING |
2 |
Return status value (ALARM – 2, WARNING – 1, or OK – 0) when instance specified by parameter “RAC instances” is missing i the gv_$instance performance view. |
| RAC instances |
|
List of instances in RAC to be checked. If the instance name is not present in the gv_$instance view the dbWatch-job will sent a warning or an alarm (based on parameter value “return status when instance is MISSING“) |
Job Summary
- Purpose: The purpose of this job is to monitor the status of Oracle RAC (Real Application Clusters) instances and react if any instances are unresponsive, not open, or missing from the Oracle global view.
- Why: Monitoring RAC instances is critical to ensure all instances in the database cluster are operational. If instances are down or not open, it could lead to degraded performance or even service outages, affecting applications relying on the database.
- Manual checking: You can check the RAC instance status manually by issuing the following SQL commands in Oracle:
SELECT inst_id, instance_name, host_name, startup_time, status, logins, shutdown_pending, database_status FROM gv$instance;
Implementation Details
- The stored procedure “rac_instances_status” checks the status of each instance defined for monitoring. It examines if any instance status is not ‘OPEN’ and also checks if any instance is missing based on a predefined list of RAC instances.
- For instances not ‘OPEN’, and for missing instances, different return statuses can be configured which aid in generating appropriate alarms or warnings.
- The procedure manages several counts and statuses to track and return the overall system state.
- Dependencies require the procedure to have SELECT privilege on gv_$instance.
Monitoring Schedule
- The job is scheduled to run every minute as indicated by the default schedule setting (‘* * * *’), meaning it checks the RAC status very frequently to ensure timely detection of issues.
Reports
- A comprehensive report can be generated which summarizes the status of all Oracle RAC instances monitored. This report pulls data directly from the gv$instance view to provide up-to-date information on instance statuses.
Parameters (Not Described)
- Parameters to exclude certain instances or alter the return status based on instance conditions are supported, enabling customization as per specific requirements.
Dependencies
- The job itself acts as a dependency, ensuring reliable operation and self-check capability.
Recovery and Cleanup
- If the job faces a failure during execution, cleanup routines are set up to handle and rectify any disruptions caused to the system.
This monitoring job represents a crucial aspect of managing Oracle RAC environments, ensuring high availability and reliability by actively monitoring and reporting the status of RAC instances.