Use this Knowledge Script to monitor the following parameters for Oracle RAC:
Redo Log Contention: the number of times that a process tries to write an entry in the redo log buffer. The job raises an event and than stores data if the number of tries is different for subsequent iterations of the script.
The number of retries should be low. A high number of retries can adversely affect system performance, as processes must wait for buffers. If a process has to make numerous attempts to write an entry in the redo log buffer, you might need to allocate more space to the redo log buffer.
You can set a threshold value for the maximum number of times a process can try to write an entry in the redo log buffer. If the number of retries exceeds the threshold, an event is raised.
Redo Log Space Wait Ratio: the redo log space wait ratio. The redo log space wait ratio measures memory allocation. The ratio reflects the number of times the background process was requested to allocate space within the redo file per number of redo log entries. If this ratio increases, you might want to increase the size of the redo log buffer.
When the redo log space wait ratio exceeds the threshold you set, the job raises an event.
Redo Logs Not Archived: retrieve the number of redo logs that are not being archived, if archiving is turned on for a given Oracle database. The number of redo logs not archived is returned and compared against the thresholds you specify. The Knowledge Script retrieves the archive status dynamically for an Oracle RAC database.
When you enable data collection, the number of redo logs not archived is stored in the repository.
The account you use to run this script must have SELECT permissions for the following tables:
V_$SGASTAT
V_$SYSSTAT
V_$VERSION
V_$LOG
This Knowledge Script is supported on Oracle 11gR2 and Oracle 12c.
Oracle RAC Database Instance. When you drop a script on an Oracle RAC Database Instance, a job executes on that database Instance and monitors only that database Instance.
The default interval for this script is Every 10 minutes.
Set the following parameters as needed:
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Description |
How to Set It |
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General Settings |
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Cluster(s) to exclude |
Enter the cluster names to exclude with a comma (,) between each cluster name, to exclude the cluster from all jobs. |
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Database Instance(s) to exclude |
Enter the database instances to exclude with a comma (,) between each database name, to exclude the database from all jobs. |
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Event detail format |
Select one of the following formats in which to view all events:
The default is HTML Table. |
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Event severity when job fails |
Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 5 (red event indicator). |
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Enable debugging? |
Select Yes to enable debugging. The default is deselected. |
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Raise event when AppManager fails to get metrics? |
Select Yes to raise an event when AppManager fails to get the metrics. The default is Yes. |
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Event severity |
Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 5 (red event indicator). |
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Event Settings |
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Raise event if threshold is exceeded for Redo Log Contention? |
Select Yes to raise an event if the number of times that a process tries to rewrite an entry to the redo log buffer exceeds the threshold you set. The default is unselected. |
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Threshold - Maximum redo log buffer allocation retries |
Enter a threshold for the maximum number of times that a process might try to rewrite an entry to the redo log buffer before the job raises an event. The default is 50 retries. |
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Severity |
Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 5 (red event indicator). |
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Raise event if threshold is exceeded for Redo Log Space Wait Ratio? |
Select Yes to raise an event if the redo log space wait ratio exceeds the threshold you set. The default is Yes. |
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Threshold - Maximum redo log space wait ratio |
Enter a maximum threshold for the redo log space wait ratio. The default ratio is 0.0002. |
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Severity |
Set the event severity level, from 1 to 40, to indicate the importance of the event. The default is 5 (red event indicator). |
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Raise event if threshold is exceeded for Redo Logs not Archived? |
Select Yes to raise an event if the threshold exceeds the value you specified.The default is Yes. |
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Threshold - Maximum number of redo logs not archived |
Specify a threshold for the maximum number of redo logs that have not been archived. The default is 6 redo logs. |
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Severity |
Set the event severity level, from 1 to 40, to indicate the importance of the event. The default severity level is 5 (red event indicator). |
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Data Collection |
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Collect data for… |
Select Yes to collect data for charts and reports. When you enable data collection, and if monitoring of each metric is enabled, the Knowledge Script returns the following statistics for each Redo script that is running:
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