IBM SC34-7012-01 Defining system and general log streams, System logging, recovery purposes only

Chapter 11. Defining system and general log streams

All CICS system logging and journaling is controlled by the CICS log manager, which uses MVS system logger log streams to store its output.

About this task

CICS logging and journaling can be divided into four broad types of activity:

System logging

CICS maintains a system log to support transaction backout for recoverable resources. CICS implements system logging automatically, but you can define the log stream as DUMMY to inhibit this function. However, if you specify TYPE(DUMMY) for the system log, you are running without any transaction backout facilities and without any restart capability, and you can start CICS with START=INITIAL only.

CICS also supports programming interfaces that enable you to write your own data to the system log, but user-written records should be for

recovery purposes only.

See “Defining system log streams” on page 108.

Forward recovery logging

CICS supports forward recovery logs for VSAM data sets.

Forward recovery logging is not automatic—you must specify that you want this facility for your files, and also define the forward recovery log streams.

See “Defining forward recovery log streams” on page 116.

Autojournaling

CICS supports autojournaling of file control data and terminal control messages. Autojournaling is generally used for audit trails.

Autojournaling is not automatic—you must specify that you want this facility for your files and terminal messages, and also define the general log streams to be used.

See the JOURNAL attribute described in FILE and PROFILE resource definition attributes in the CICS Resource Definition Guide for information about specifying automatic journaling on FILE and PROFILE resource definitions.

User journaling

CICS supports programming interfaces to enable CICS applications to write user-defined records to user journals, which are held on general log streams.

See the CICS System Definition Guide for information about defining general log streams for user journals.

Autojournaling and user journals play no part in CICS recovery and therefore are not discussed here.

The CICS log manager writes the data associated with these logging and journaling activities to two types of MVS log stream:

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