Mainframe Batch Window Optimization: Lessons from a 40,000-Jobs batch cycle

Several years ago, I worked with a colleague on a Mainframe Batch Window Reduction initiative for a customer. The batch processing window ran from 7:00 PM to 10:30 PM, during which approximately 40,000 batch jobs were executed. The batch cycle contained around 10 critical processing paths.

Interestingly, nearly 99% of the 40,000 jobs completed within one minute, while only a handful of jobs had execution times ranging from 5 to 10 minutes. Most of the jobs were running every 1 minute.

We applied following techniques to reduce the batch window. As a result we introduced about 45 minutes of slack time in 5 critical paths

• Removed unwanted job dependencies
• Worked with upstream applications to get input files early
• Moved non-critical jobs out of the critical paths where feasible.
• Preponed the time triggered jobs
• Converted sequential DB2 unload steps to parallel jobs
• Replaced IDCAMS steps with SORT where feasible.
• Replaced DSNTIAUL unload steps with BMC UNLOAD where feasible.
• Replaced BMC UNLOAD step by image copy where feasible.