Contingency Plan

Enhanced Definition

A contingency plan in the mainframe context is a predefined, documented set of procedures and strategies designed to ensure the continued operation of critical z/OS systems, applications, and data in the event of a disruptive incident or disaster. Its primary purpose is to minimize downtime and data loss, enabling the organization to recover and resume normal business operations within acceptable timeframes. A formal, documented strategy and set of procedures designed to enable an organization to respond to and recover from unexpected events (disasters, outages, data loss) that disrupt critical mainframe operations, ensuring the continuity of essential business functions. It outlines the steps to restore `z/OS` systems, applications, and data to an operational state within predefined timeframes.

Key Characteristics

- Proactive Planning: Involves identifying potential risks, assessing their impact, and developing strategies *before* an incident occurs.
- Recovery Time Objective (RTO) & Recovery Point Objective (RPO): Specifies the maximum acceptable downtime and maximum acceptable data loss, respectively, for critical systems and applications.
- Alternate Site Utilization: Often involves establishing or contracting with an off-site data center (hot, warm, or cold site) to host recovered systems and data.
- Comprehensive Scope: Covers not just technical recovery but also personnel, communication, facilities, and business process restoration.
- Regular Testing and Validation: Requires periodic testing of the plan to identify gaps, validate procedures, and ensure the plan remains effective and current.
- Documentation: Detailed, accessible documentation of all recovery procedures, contact lists, and system configurations is essential.

Use Cases

- Disaster Recovery (DR): Responding to major catastrophic events like natural disasters (floods, earthquakes), widespread power outages, or data center destruction.
- Business Continuity (BC): Maintaining essential business functions during less severe but significant disruptions, such as a major hardware failure, network outage, or cyberattack.
- Application-Specific Recovery: Restoring critical applications (e.g., CICS regions, DB2 subsystems, IMS control regions) and their associated data after corruption or failure.
- Data Restoration: Recovering specific datasets, volumes, or entire storage groups using backups (e.g., from tape or disk) following accidental deletion or corruption.
- System Software Rollback: Planning for the ability to revert to a previous stable z/OS or subsystem configuration if a new software deployment causes critical issues.

Related Concepts

Contingency planning is a foundational component of Disaster Recovery (DR) and Business Continuity (BC) strategies. It heavily relies on robust Backup and Recovery procedures, utilizing tools like DFSMSdss, ADSM/TSM, or DFSMShsm for data protection. It often integrates with High Availability (HA) solutions (e.g., GDPS, Sysplex, XRC, PPRC) which aim to prevent downtime, whereas contingency plans focus on recovery *after* an outage. Effective plans also consider Workload Manager (WLM) policies to prioritize critical workloads during recovery and System Automation tools to streamline recovery processes.

Best Practices:

Define Clear RTOs and RPOs: Establish realistic and measurable recovery objectives for all critical business processes and their supporting IT systems.
Regular, Documented Testing: Conduct full -scale, end-to-end recovery tests periodically (e.g., annually) and document the results, lessons learned, and any necessary plan updates.
Maintain Up-to-Date Documentation: Ensure all recovery procedures, system configurations, contact lists, and software inventories are current and readily accessible, even off-site.
Geographic Diversity: For critical systems, ensure backup data and alternate recovery sites are geographically separated from the primary site to mitigate regional disaster risks.
Personnel Training and Cross-Training: Train multiple staff members on recovery procedures to ensure continuity of expertise and reduce reliance on single individuals.
Automate Recovery Steps: Where possible, use JCL, REXX, or system automation tools to automate recovery tasks, reducing human error and speeding up the recovery process.