A customer has run the IBM Processor Capacity Reference tool (zPCR) and asks for advice on a planned z14 upgrade. What is the first concern an IBM Z Client Technical Specialist should address?

Question

Options

• AConsult the LSPR MIPS planning chart.
• BExamine the zPCR results to determine the needed z14.
• CVerify results by cross checking LSPR Gartner MIPS values.
• DDetermine if the actual customer workloads match the workload definitions used in zPCR.

• A
  28% (11)
• B
  5% (2)
• C
  13% (5)
• D
  55% (22)

Explanation

Option D is correct because zPCR models capacity using specific, predefined workload definitions (e.g., commercial interactive, batch, Java), and if the customer's actual workloads don't match those definitions, the tool's output is fundamentally unreliable - no matter how precise the numbers look. This is the "garbage in, garbage out" principle: validating the model's assumptions must come before interpreting its results.

Why the distractors fail:

• A (LSPR MIPS chart) is a useful planning reference, but consulting it before confirming zPCR's workload alignment skips the essential validation step.
• B (Examine zPCR results) is exactly what you do after D - acting on results before verifying the inputs can lead to a costly, wrong-sized upgrade.
• C (Cross-check Gartner MIPS) is a verification technique, but verifying one set of potentially flawed numbers against another doesn't fix the root problem of mismatched workload definitions.

Memory tip: Remember "Validate Before You Calculate." zPCR is only as good as the workload profile fed into it - the specialist's first job is to confirm the model reflects reality, not to trust the output at face value.

No community discussion yet for this question.