z/OS log data set

The IMS Common Queue Server (CQS) records information about the data in the IMS shared queues in the z/OS® log data set. The z/OS system logger serves the same purpose for CQS as the OLDS serves for IMS: it records all necessary information so CQS can recover structures in the coupling facility and restart after failure.

CQS writes log records for each pair of coupling facility list structures to a separate log stream. This log stream is shared among all the CQS subsystems that share the structure pair. z/OS merges the log streams to make recovery possible.

Related reading:  For more information on the z/OS system logger, see Using System Logger Services in z/OS MVS Programming: Assembler Services Guide.