CMF - CICS Monitoring Facility

Enhanced Definition

CMF, the CICS Monitoring Facility, is an integral component of IBM CICS Transaction Server for z/OS that collects detailed performance and resource utilization data for CICS transactions and regions. It provides critical insights into the operational health and efficiency of CICS workloads, enabling performance analysis, problem determination, and capacity planning. CMF, or CICS Monitoring Facility, is a core component of CICS Transaction Server for z/OS that collects detailed performance and resource utilization data for CICS transactions, programs, and the CICS region itself. It provides critical insights into the health, efficiency, and resource consumption of CICS applications and the underlying CICS system.

Key Characteristics

- Comprehensive Data Collection: Gathers extensive performance metrics, including CPU usage, elapsed time, I/O counts, storage usage, program execution details, file accesses, and database (DB2/IMS) calls for individual transactions and the CICS region.
- SMF Integration: Primarily writes collected monitoring data to SMF (System Management Facilities) type 110 records, making it a standard source for CICS performance data within the z/OS ecosystem.
- Configurable Monitoring Levels: Allows administrators to control the granularity and type of data collected through CICS system initialization parameters (SIT parameters) and resource definitions, balancing data detail with system overhead.
- Transaction and System Level Data: Collects both transaction-level data (specific to each executed transaction) and system-level data (aggregated statistics for the entire CICS region).
- Overhead Management: While essential, CMF data collection introduces some CPU and I/O overhead, which must be carefully managed through selective monitoring to avoid impacting CICS performance.

Use Cases

- Performance Tuning: Identifying slow-running transactions, resource bottlenecks (e.g., excessive CPU, I/O waits, storage contention), and inefficient application code within CICS applications.
- Problem Determination: Diagnosing transaction abends, deadlocks, or unexpected delays by analyzing the sequence of events, resource consumption, and program execution paths captured by CMF.
- Capacity Planning: Forecasting future resource requirements (CPU, memory, DASD, network) for CICS environments based on historical workload trends and growth patterns.
- Service Level Agreement (SLA) Validation: Monitoring and reporting on key performance indicators like transaction response times to ensure CICS applications meet defined service level objectives.
- Chargeback and Cost Allocation: Providing granular data to attribute resource consumption and associated costs to specific applications, departments, or business units for financial management.

Related Concepts

CMF is fundamental to CICS management, providing the raw performance data that underpins all CICS operational insights. Its primary output, SMF type 110 records, makes it a vital contributor to the broader z/OS performance monitoring framework, where JCL is often used to execute batch jobs that process these records. The data collected by CMF is frequently consumed and visualized by third-party performance monitors like OMEGAMON for CICS or CA SYSVIEW, which provide real-time and historical analysis capabilities.

Best Practices:

Selective Monitoring: Configure CMF to collect only the necessary data using SIT parameters (e.g., MN=ON, MNPER=ON, MNRES=ON, MNCLASS) to minimize overhead while still gathering sufficient information for analysis.
Regular SMF Offloading: Ensure that SMF data sets are regularly offloaded and processed to prevent data loss, maintain data integrity, and enable timely performance analysis.
Establish Baselines: Create performance baselines for critical CICS transactions and regions using CMF data to quickly identify deviations, performance degradations, or abnormal behavior.
Automated Analysis Tools: Leverage automated tools or custom programs to parse, analyze, and report on CMF data, generating alerts for performance thresholds or anomalies.
Security and Access Control: Restrict access to CMF configuration parameters and collected data to authorized personnel to prevent unauthorized changes and protect sensitive performance information.