SLDS recovery

The Log Recovery utility closes a system log data set (SLDS) created by an IMS batch job. You must close an SLDS before you can use it as input to any utilities or to an IMS restart.

The Log Recovery utility recovers the SLDS from the following types of errors:

• An I/O error while reading the input log data set
• An error in the log record
• A log record sequence error

To recover an SLDS, the Log Recovery utility reads the SLDS based on the mode that it is in:

• In DUP mode, the utility reads an SLDS and duplicates all readable log records onto an interim log. When the utility encounters the first error or end of file (EOF), it stops copying and closes the SLDS. When you specify a nonzero error count, DUP mode writes error blocks and error ID records on the interim log until either the error count reaches the number you specify or EOF is reached. The utility uses the interim log containing these error blocks and error ID records as input to REP mode.

  You can close an SLDS by using DUP mode and specifying the error count as zero. REP mode is not required.

• In REP mode, the utility reads the interim log created by DUP mode, copies good log blocks, and replaces error blocks with good ones based on information that you specify in control statements. The output log data set is a usable SLDS.