Intervention - Manual action
In the context of IBM mainframe systems and z/OS, an "intervention" or "manual action" refers to a required human interaction with the system, typically performed by an operator, system programmer, or administrator. These actions are necessary to resolve exceptional conditions, provide specific input, or initiate processes that cannot be fully automated, ensuring the continued operation or recovery of critical workloads.
Key Characteristics
-
- Human-Initiated: Requires direct human involvement, often in response to system messages or specific operational needs.
- Event-Driven: Frequently triggered by system events, such as
WTOR(Write To Operator with Reply) messages, resource contention, or application failures. - Non-Routine or Exception Handling: While some interventions (like tape mounts) can be routine, many are responses to unexpected errors, resource shortages, or security alerts.
- Console-Based: Typically performed via the system console (e.g.,
SDSF,NetView,SA z/OSconsole interfaces) using specific operator commands. - Impact on Throughput: Can introduce delays in job processing or system availability if not handled promptly and correctly.
- Auditable: All significant manual actions and console commands are logged in the system console log (
SYSLOG) for auditing, problem determination, and compliance.
Use Cases
-
- Responding to
WTORMessages: Operators providing input or making decisions in response to messages from applications or the operating system (e.g.,REPLY XX,'Y'to continue a process). - Mounting Physical Media: Instructing operators to mount specific tape volumes or physical disk packs for backup, restore, or batch processing, though less common with virtualized storage.
- System Recovery and IPL: Performing manual steps during an Initial Program Load (IPL), especially for cold starts or disaster recovery scenarios, involving console commands and system parameter selections.
- Subsystem Management: Manually starting or stopping critical subsystems like CICS, DB2, or IMS, or canceling runaway jobs that are consuming excessive resources.
- Security Incident Response: Intervening to lock user IDs, reset passwords, or manually override access controls in emergency situations following a security breach or policy violation.
- Responding to
Related Concepts
Manual interventions are often a last resort when automation strategies, such as those implemented with JCL, REXX, or automation products like SA z/OS and NetView, are insufficient or fail. They are intrinsically linked to system console operations, where operators monitor the SYSLOG and issue commands. Effective error handling within applications and robust system monitoring tools are crucial to minimize the need for interventions and provide clear guidance when they are unavoidable. Furthermore, they are a critical component of Disaster Recovery (DR) and Business Continuity Planning (BCP), where specific manual steps are often required to restore services.
- Automate Aggressively: Prioritize the automation of recurring manual tasks using JCL, REXX scripts, CLISTs, and enterprise automation tools (e.g.,
SA z/OS,NetView) to reduce human error and improve efficiency. - Clear Documentation and Runbooks: Maintain comprehensive, up-to-date runbooks and procedures for all required manual actions, including expected system messages, required responses, and escalation paths.
- Operator Training and Empowerment: Ensure operators are thoroughly trained on common intervention scenarios, system messages, console commands, and the appropriate decision-making processes.
- Prompt Response Protocols: Implement clear protocols and monitoring to ensure timely responses to
WTORmessages and other alerts, preventing system bottlenecks or job delays. - Audit and Continuous Improvement: Regularly review
SYSLOGentries and incident logs related to manual interventions to identify recurring issues, potential automation opportunities, and areas for process or application improvement.