Enterprise Manager stores statistical data until the system reaches the storage capacity, which is by default, 1 GB stored locally. When this capacity is met, the oldest data in the system is replaced with new data, up to the storage limit. This default amount is intentionally low because when you enable statistics collection it affects the overall performance of the system. Therefore, it is important to plan for your database storage needs by understanding your system's capacity and personalize your storage requirements so you can maximize the value of the statistics features. Once you have estimated the availability of storage on your system, you can change the default database storage capacity setting. Increasing the default setting is essential to monitoring statistics data over time.
To help you plan for statistics storage, you can view the system's hard drive allocation by file type to remove any unnecessary files and calculate statistics data storage.
This number is calculated based on the current rate of data collection and the amount of disk space you specified for the storage space allocation. To retain more or less historical data, you can change the storage allocation space. To help you determine how much disk space you want to allocate to statistics storage, you can recalculate the estimated number of storage days by modifying the storage space. When you have determined that you are satisfied with the storage space value, you can then opt to save the changes.
By default, Enterprise Manager™ stores health and performance monitoring statistics data in the database located on its hard drive. You have the option of configuring Enterprise Manager to store these statistics on a hard drive that is separate (external) from the Enterprise Manager system. Storing statistics on an external database clears space on Enterprise Manager for more storage of archives, images, configuration files, and so forth. A space dedicated only to health and performance monitoring statistic data can also provide you with more historical data storage.
To use an external database for health and performance monitoring statistics storage, you must create the external database and then configure Enterprise Manager to store data on that database.
If you previously collected data locally on the Enterprise Manager system, you have the option to back up and restore the data to the external database.
Before configuring Enterprise Manager™ to store statistics data on an external database, you must create an external database on a system that is running Oracle® MySQL® version 5.1 with patch 52 or later.
If you previously collected data locally on the Enterprise Manager™ system, you can back up and restore the local data to the external database that you created.
After you have created the external database on the remote system, you can configure Enterprise Manager™ to store data there.
Configuring Enterprise Manager to store health and performance monitoring statistics on an external database frees system resources, and provides you with space to store statistics that is limited only by the system's hard drive on which you configure the external database.
If you have two Enterprise Manager systems configured as a high availability system, configure the external database the same way on each system.
You can backup and restore the statistics database from the command line, or you can create a task to backup the statistics database on a regular schedule.