Operations, scheduling and production support

Lessons

1. What production support actually is
   Production support keeps the business running on top of systems written by people who left years ago. It is part detective work, part risk judgement, and it rewards method over…
2. The batch schedule and the critical path
   Thousands of jobs run every night in a dependency order held by a scheduler. The schedule, not the JCL, is the real map of the overnight — and one chain through it determines…
3. Triage: an abend at three in the morning
   A method beats intuition here, especially when you are half awake. This sequence works on any job in any application, and it is what experienced people actually do.
4. Rerun, restart, and not making it worse
   The riskiest moment in production support is the decision about what to run again. Rerunning something that already updated data can double-post transactions; skipping something…
5. Change, incidents and doing this sustainably
   The last part of the job is the part that keeps you employed and rested: making changes safely, running incidents calmly, and steadily reducing the number of things that go wrong.