Message log overview

The IMS Command Control Facility message log provides a single point of reference for reviewing IMS messages, commands, and command responses. The message log provides a single point of reference for IMS system monitoring and problem determination.

IMS Command Control Facility uses the IMS automated operator exit (DFSAOE00) to capture a copy of IMS messages, commands, and command responses and write them to a message log.

Additionally, IMS Command Control Facility provides post-exit routines that capture commands and command responses from the IMS Operations Manager (OM) and write them to the same message log. These routines can be added to the IMS OM task to capture copies of commands and responses for the IMS OM.

The message log is defined as a z/OS® system logger log stream. System logger is a z/OS component that provides a logging facility for applications that run in a single-system or multi-system sysplex.

The advantage of using system logger is that the responsibility for tasks such as saving the log data (with the requested persistence), retrieving the data (potentially from any system in the sysplex), archiving the data, and expiring the data is removed from the creator of the log records. In addition, system logger provides the ability to have a single merged log that contains log data from multiple instances of an application within the sysplex.

You can define the system logger log stream either as DASD-only or to the coupling facility:

• Define the log stream as DASD-only if the log stream needs to be shared on the same z/OS image

  If you do not have a coupling facility, you must define the log stream as DASD-only.

• Define the log stream to the coupling facility if the log stream will not be shared across multiple MVS LPARs

The log stream can be shared by IMS regions that run anywhere in the z/OS sysplex. The log stream must be defined to the coupling facility in order for it to be shared (read or update) by multiple z/OS images.

An archive job is provided to unload the log stream to a sequential data set. You can save the sequential data set for historical reference purposes. The archive job provides parameters to determine how much data is to be archived, or left in the log stream.

You can view the active message log by using the IMS Command Control Facility ISPF dialog. The IMS Command Control Facility ISPF dialog provides several options to filter the log data to be displayed. The following filter options are available:

• IMS region
• User ID
• Date/time interval
• All active log data

Data stored in the log stream

IMS Command Control Facility writes records to the log stream in the order in which they are presented to the IMS automated operator interface (AOI) and Operations Manager (OM) exits.

The data remains in the log stream until it is either marked for deletion by IMS Command Control Facility or automatically deleted by the z/OS system logger.

If the log data is required for historical purposes, you should set the retention period in the z/OS system logger policy high enough so that the data is not deleted before the IMS Command Control Facility archive job can offload the data.