A customer has multiple IBM Z servers in their z/OS environment. Which of the following is designed to provide 99.999% application availability?

Question

Options

• Az/VM hosting z/OS guest systems
• BParallel Sysplex
• CSingle System Image (SSI)
• DDynamic Partition Manager

• B
  92% (23)
• C
  4% (1)
• D
  4% (1)

Explanation

Parallel Sysplex is IBM's clustering technology specifically engineered to deliver "five nines" (99.999%) availability by linking multiple z/OS systems so they share workload and can survive individual system failures without application downtime. It uses the Coupling Facility and XCF (Cross-System Coupling Facility) to coordinate resources across systems, enabling continuous operation even during planned maintenance or unplanned outages.

Why the distractors are wrong:

• A (z/VM hosting z/OS guests): z/VM provides virtualization and consolidation, but hosting guest LPARs doesn't inherently deliver high availability - a hypervisor failure can still take down all guests.
• C (Single System Image / SSI): SSI allows multiple z/OS instances to share a DASD pool and simplifies management, but it's a management feature, not a high-availability solution.
• D (Dynamic Partition Manager): DPM is a workload-based partition management tool for resource allocation; it has no built-in availability or failover capability.

Memory tip: Think of the word "Sysplex" - SYStem comPLEX - as a complex of systems working together. Any time the exam mentions five-nines availability across multiple Z servers, the answer will be Parallel Sysplex, because it's the only IBM Z technology purpose-built for cross-system failover and continuous availability.

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