Oracle Enterprise Manager (OEM) 13c is Oracle’s centralized monitoring and management framework used to manage databases, hosts, middleware, applications, and enterprise infrastructure from a single console.
Understanding the core components of OEM is essential for DBAs and system administrators to effectively deploy, monitor, and troubleshoot the environment.
OMS – Oracle Management Service
The Oracle Management Service (OMS) is a web-based application that acts as the brain of the OEM architecture.
OMS orchestrates communication with the Management Agents and plug-ins to discover targets, monitor and manage them, and store the collected information in a repository for future analysis.
- Receives data from Management Agents
- Coordinates monitoring activities
- Processes alerts and incidents
- Serves data to the OEM Console
- Runs as WebLogic managed server
OMR – Oracle Management Repository
The Oracle Management Repository (OMR) is the central storage location where all monitoring data is stored.
It is a database schema that contains:
- Database jobs
- Packages and procedures
- Views and tables
- Historical performance data
- Target configuration details
OMR is typically hosted on a dedicated Oracle Database (19c recommended) for better performance and stability.
Management Agent
The Management Agent is a lightweight software component installed on every host that needs to be monitored.
It converts an unmanaged host into a managed host within the OEM ecosystem.
- Collects metrics from targets
- Executes jobs and scripts
- Communicates with OMS
Types of Management Agents
- Central Agent: Installed automatically with OMS and used to monitor the OMS host itself.
- Standalone Target Agent: Installed on remote hosts to monitor databases, applications, and servers.
Targets
Targets are the entities that can be monitored within an enterprise.
Managed targets include:
- Hosts
- Databases
- Application servers
- Applications
- Listeners
BI Publisher
Oracle BI Publisher is the primary reporting tool used in OEM.
- Highly formatted reports
- Dashboards and summaries
- Compliance and audit reports
Connectors
Connectors allow OEM to integrate with third-party tools.
They act as a mediator between OEM and external systems such as:
- BMC Remedy
- ServiceNow
- Other ticketing systems
Connectors enable automatic ticket generation from OEM incidents.
JVMD Engine
The Java Virtual Machine Diagnostics (JVMD) Engine helps diagnose performance issues in Java applications.
- Thread analysis
- Memory usage
- Garbage collection behavior
OEM Console
The OEM Console is the graphical user interface of the Enterprise Manager system.
It provides a single-pane-of-glass view for:
- Monitoring all targets
- Viewing alerts and incidents
- Analyzing performance metrics
- Managing jobs and patches
EMCLI
The Enterprise Manager Command Line Interface (EM CLI) enables automation and scripting.
emcli login -username=sysmanemcli login
emcli sync
emcli logout
emcli list_targets
emcli get_targets
emcli add_target
emcli get_supported_platforms
emcli create_job
emcli get_jobs
emcli get_blackout_details
EMCTL
EMCTL is used to control OMS and Management Agents.
emctl start omsemctl stop oms
emctl start agent
emctl start agent
emctl stop agent
emctl stop agent
emctl status agent
emctl upload agent
emctl reload agent
emctl clearstate agent
emctl start blackout Blackout_name
emctl secure agent
emctl unsecure agent
Plug-ins
Plug-ins extend OEM capabilities to manage different technologies.
By default, OEM 13c includes:
- Oracle Database
- Oracle Fusion Middleware
- Oracle Exadata
- Oracle Cloud Framework
- Oracle System Infrastructure
Additional plug-ins can be installed as required.
Without plug-ins, OEM cannot discover or manage specific target types.
Conclusion
Oracle Enterprise Manager 13c provides a powerful and modular architecture for enterprise monitoring. Each component plays a critical role in ensuring visibility, automation, and proactive management of IT systems.
Please feel free to ask. Thank you 🙂
Toufique Khan
