EM 13c: How to Modify the Default Retention and Purging Policies for Metric Data in the Enterprise Manager Repository
Last updated on DECEMBER 16, 2017
Applies to:Enterprise Manager Base Platform - Version 184.108.40.206.0 to 220.127.116.11.0 [Release 13.1 to 13.2]
Information in this document applies to any platform.
This document explains the policies in Enterprise Manager Cloud Control 13c version.
For 12c version policies, please refer the following document:
<Note 1405036.1> EM 12c: How to Modify the Default Retention and Purging Policies for Metric Data in the Enterprise Manager Repository
The metric data that is collected and uploaded by the Agents on the targets hosts is called 'raw' data, which is stored by the OMS into the repository tables. Enterprise Manager aggregates collected metric data by hour and by day to enhance query performance and help minimize the size of the Management Repository. One of the DBMS_SCHEDULER Job (Rollup job) in the Repository is responsible for rolling up / aggregating this raw data. Once a day, the previous day's raw metric data is rolled up, or aggregated, into a one-hour and a one-day table. These hourly and daily records will have hourly and daily metric data averages, minimums, maximums and standard deviations respectively. The Hourly and Daily tables are used for providing historical metric information for the metrics in the Cloud Console UI pages.
The 3 tables that store this data are:
After Enterprise Manager aggregates the data, the data is then considered eligible for purging. A certain period of time must pass for data to actually be purged. This period of time is called the retention time.
The goal of this document is to provide information on how to modify the default Retention and Purging Policies in the 13c Cloud Control.
1. The Enterprise Manager default aggregation and purging policies were designed to provide the most available data for analysis while still providing the best performance and least disk-space requirements for the Management Repository. As a result, you should not modify these policies to improve performance or increase your available disk space.
However, if you plan to extract or review the raw or aggregated data using data analysis tools other than Enterprise Manager, you may want to increase the amount of raw or aggregated data available in the Management Repository. While doing this, also consider increasing the amount of disk space for the Repository related Tablespaces in the Repository Database.
2. It is essential that the DBMS_SCHEDULER feature is enabled in the Repository Database for execution of all the Repository maintenance operations. You can view the 'Oracle Scheduler Status' in the Setup -> Management System and Repository -> Repository Operations page of the 13c console. If the scheduler is disabled, then use the steps in:
Enterprise Manager Cloud Control Administrator's Guide
Chapter 20 Maintaining and Troubleshooting the Management Repository
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