Using the IMS monitor

DBCTL enables CICS® users who do not have an IMS/VS DB/DC or IMS/DM/TM system to use the IMS monitor online. The IMS monitor is the main tool provided by IMS for monitoring. It collects data from the system while it is running. It formats and records significant events during execution, and is useful in tuning constrained systems.

Monitoring data is written to a separate data set or tape defined by the IMSMON DD statement in the DBCTL JCL. To define this data set or tape and to run the IMS monitor with DBCTL, add an IMSMON DD statement to your DBCTL JCL. For further guidance, see System definition in IMS product documentation.

To allocate an IMSMON data set, use the IEFBR14 utility to allocate a data set without any DCB parameters; for example: 
//ALLOC     EXEC PGM IEFBR14
//IMSMON DD DISP=(NEW,CATLG),UNIT=3380,VOL=SER=xxxxxx,SPACE=(CYL,(5,5))
You can start and stop the IMS monitor dynamically using the /TRACE command with the MON keyword. For example: 
/TRACE SET ON MON ALL
gives you all the activity that the monitor collects. For guidance on using the /TRACE command and its keywords more selectively, see Operations and automation in IMS product documentation.
The IMS monitor has two phases:
  • During the first phase, the monitor programs collect the data and store it on either disk or tape.
  • During the second, the data is retrieved from the data set, and is organized and printed.

The data collected by the monitor (also known as DFSMNTR0) is organized and printed by the IMS monitor report print program, DFSUTR20. See Database utilities in IMS product documentation for guidance on using the IMS monitor report print utility, DFSUTR20, and for information about using the IMS monitor to identify constraints.