To be sure that your management data is secure, reliable, and always available, consider the following settings and configuration guidelines when you are deploying the Management Repository:
Install a RAID-capable Logical Volume Manager (LVM) or hardware RAID on the system where the Management Repository resides. At a minimum the operating system must support disk mirroring and stripping. Configure all the Management Repository data files with some redundant configuration.
Use Real Application Clusters to provide the highest levels of availability for the Management Repository.
If you use Enterprise Manager to alert administrators of errors or availability issues in a production environment, be sure that the Cloud Control components are configured with the same level of availability. At a minimum, consider using Oracle Data Guard to mirror the Management Repository database. Configure Data Guard for zero data loss. Choose between Maximum Availability or Maximum Protection based on your environment and needs.
Oracle Database High Availability Architecture and Best Practices
Oracle Data Guard Concepts and Administration
Oracle strongly recommends that archive logging be turned on and that a comprehensive backup strategy be in place prior to an Enterprise Manager implementation going live in a production environment. The backup strategy should include archive backups and both incremental and full backups as required.
Oracle Enterprise Manager Cloud Control Installation and Basic Configuration for information about the database initialization parameters required for the Management Repository
Oracle recommends that you not use SQL Plan Management (SQL plan baselines and capture) with the Enterprise Manager Cloud Control repository. If you do need to use it for a specific problem, shut it off immediately after using. Issues with the Enterprise Manager Cloud Control repository may occur when using SQL Plan Management, such as very poor SQL performance using unverified plans, and deadlocks between SQL Plan Management capture and the Enterprise Manager security VPD.
After enabling auditing for the repository database and for audit entries related to ORA- errors, error messages should be ignored if they are not reported in the Enterprise Manager application logs; for example, emoms.trc, the MGMT_SYSTEM_ERROR_LOG table, or in the alert.log of the repository database. In these cases the errors are harmless.
To see a list of the regular maintenance activities that need to be performed for the repository, see the Sizing Your Enterprise Manager Deployment in the Oracle® Enterprise Manager Cloud Control Advanced Installation and Configuration Guide.
To monitor the repository database activities using the Enterprise Manager user interface, see Maintaining Enterprise Manager.