Escalate

Priority Increase

Enhanced Definition

In the context of IBM z/OS and mainframe systems, "escalate" primarily refers to the act of increasing the **dispatching priority** of a workload, task, or job. This action is taken to ensure that critical processes receive preferential access to CPU and system resources, allowing them to complete more quickly or meet specific service level objectives. In the context of IBM mainframe systems and z/OS, "escalate" primarily refers to the act of increasing the priority of a task, job, incident, or problem to ensure it receives more immediate attention and resources. This action is typically taken when a workload is critical, falling behind schedule, or an issue requires urgent resolution to meet service level agreements (SLAs).

Key Characteristics

- Dynamic Adjustment: Priority escalation can be performed dynamically by system operators, automated tools, or through Workload Manager (WLM) policies.
- Resource Contention Resolution: It serves as a crucial mechanism to mitigate resource contention, ensuring that high-impact applications are not unduly delayed by less critical work.
- Dispatching Priority (DP): In z/OS, escalation directly modifies the dispatching priority (DP) of an address space or task, which dictates its precedence for CPU allocation relative to other active workloads.
- Impact on System Performance: While beneficial for the escalated workload, excessive or indiscriminate priority escalation can negatively affect overall system throughput and the performance of other, potentially important, workloads.
- WLM Integration: For workloads managed by WLM, escalation can occur implicitly as WLM adjusts service classes and importance levels to meet defined goals, or explicitly via operator commands that override WLM's current decisions.
- Operator Commands: System operators frequently use commands such as VARY WLM,APPL=xx,PRIORITY=nn or MODIFY commands for specific address spaces to manually influence their priority.

Use Cases

- Critical Batch Job Completion: Increasing the priority of a nightly batch job that is running behind schedule to ensure it completes within its required window before online systems become available.
- Online Transaction System Responsiveness: Temporarily elevating the priority of a CICS region or IMS control region during peak demand to maintain optimal response times for critical online transactions.
- Problem Diagnosis and Resolution: Boosting the priority of a diagnostic utility, a dump process, or a critical recovery job to expedite problem analysis or system restoration.
- Urgent Ad-hoc Reporting: Prioritizing an urgent, unscheduled report requested by management that needs immediate execution over standard, lower-priority reporting jobs.
- Database Utility Execution: Giving higher priority to essential DB2 or IMS database reorganization, recovery, or backup utilities to minimize their impact on system availability or meet maintenance windows.

Related Concepts

Priority escalation is fundamentally linked to Workload Manager (WLM), which is the cornerstone of resource management in z/OS, aiming to automate priority adjustments based on defined service goals. It directly manipulates the dispatching priority of tasks and address spaces, a core concept in z/OS task management. This mechanism is vital for managing resource contention and ensuring that service level agreements (SLAs) are met, often interacting with concepts like service classes and importance levels defined within WLM policies.

Best Practices:

Leverage WLM Goals First: Prioritize defining appropriate WLM service classes and goals to allow WLM to automatically manage priorities, reducing the need for manual intervention.
Document and Justify: All manual priority escalations should be thoroughly documented, justified by business criticality, and ideally, temporary, with a clear plan for reversion or addressing the root cause.
Monitor System Impact: Always monitor the overall system performance and the impact on other workloads after escalating a priority, as it can inadvertently degrade the performance of other critical processes.
Avoid Indiscriminate Escalation: Refrain from widespread or frequent manual priority changes without a deep understanding of the system's workload dynamics, as this can lead to system instability and unpredictable performance.
Automate with Caution: If automating escalation, ensure the automation logic is robust, includes clear trigger conditions, incorporates a mechanism for de-escalation, and provides alerts to operators.