Monitoring unallocated z/OS storage for CICS
CICS® monitoring of unallocated z/OS® storage in the z/OS address space in which a CICS region operates helps you track and optimize the use of z/OS storage and avoid region abends due to short-on-storage (SOS) conditions.
CICS periodically monitors the following areas for the
amount of unallocated z/OS storage that is still available,
and issues console messages notifying you of fluctuations in unallocated z/OS storage and SOS events detected in these z/OS storage areas:
- z/OS user region storage in the 24-bit addressing range
- z/OS extended user region storage in the 31-bit addressing range
- 6.2 and later z/OS MEMLIMIT storage in the 64-bit addressing range
During SOS conditions that occur to z/OS user region storage and extended user region storage, the SOS wait feature, enabled by default, suspends user tasks that require a new open TCB, thus preventing the SOS conditions from getting worse and allowing the affected region to recover.
You can define SOS thresholds, or use the default thresholds, that the CICS z/OS storage monitor system task uses to determine when a CICS region is SOS for the above z/OS storage areas.
The console messages issued by CICS and the storage statistics included in Storage manager: Global statistics help you to guard against potential storage problems and give you flexibility to take whatever actions to prevent SOS events.