CICS support for IBM Health Checker for z/OS

IBM Health Checker for z/OS (Health Checker) is a z/OS component that helps simplify and automate the identification of potential configuration problems before they impact availability or cause outages. CICS TS supports Health Checker rules that define preferred practices for CICS system configuration.

Each CICS region providing support for Health Checker executes the system transaction CHCK as a long-running task. This task wakes up every 30 minutes to check and report on compliance to preferred practices. To ensure this task does not consume unnecessary CPU, two idle CICS regions were compared.

One CICS region had the Health Checker reporting enabled and the other had the Health Checker reporting disabled. Both CICS regions had security enabled (SIT parameter SEC=YES), and 25 transient data queues were installed. To ensure the most accurate reporting of CPU consumption, the CHCK transaction was specially modified to wake up every 5 seconds.

Using the overnight automation environment as described in Repeatable measurements, performance of the two CICS regions were measured while idle for a 5-minute measurement period. CPU consumption data was extracted from the CICS statistics report and is presented in Table 1. All data is presented in CPU seconds.

Table 1. Summary of CICS statistics for Health Checker CPU measurement
  CHCK disabled CHCK enabled Difference
Address space TCB time 0.003888 0.035986 0.032098
Address space SRB time 0.000349 0.000538 0.000189
Total CPU time 0.004237 0.036524 0.032287

The CICS statistics interval was 305 seconds; therefore, we can conclude the CHCK task woke up around 60 times during that time period. Also, we can calculate that the CHCK task cost approximately 540 µs of CPU per iteration.

When using the CICS support for Health Checker configuration with the standard checking frequency of 30 minutes, this functionality consumes approximately 1 ms of CPU per hour for a completely idle CICS region. In contrast, the results presented in Table 1 for the CICS region with Health Checker support disabled show a CPU consumption of approximately 50 ms per hour for other CICS background processing. Thus, we can conclude that CICS support for the IBM Health Checker for z/OS adds no significant overhead to a CICS region.

Note: CICS support for the IBM Health Checker for z/OS is also available for releases prior to CICS® TS 5.4. See APAR PI76963 for CICS TS 4.2 and APAR PI76965 for CICS TS V5 releases.

For more information about the CICS support for the Health Checker, see Checking CICS configuration with IBM Health Checker for z/OS.