This topic explains how system logger handles errors or coupling facility structure state changes, how the errors might affect applications, and what action, if any, a system programmer might need to take. For coupling facility log streams, see also Plan your configuration for log data recovery.

System logger performs recovery differently for DASD-only versus coupling facility log streams. Most of the information in this topic applies to coupling facility log streams only. For DASD-only log streams, see Recovery performed for DASD-only log streams. Other recovery information pertinent to DASD-only log streams is noted under each topic.