A customer wants to configure a specific 5GB LUN for the fastest possible response time on a Hitachi Unified Storage system. Which feature should be used?

Question

Options

• ACache Partition Manager
• BVolume Migration
• CCache Residency Manager
• DData Retention Utility

• A
  10% (5)
• B
  16% (8)
• C
  71% (36)
• D
  4% (2)

Explanation

Cache Residency Manager allows administrators to pin a specific LUN permanently in cache memory, preventing it from being evicted during normal cache replacement cycles. For a 5GB LUN where fastest response time is critical, pinning it ensures every read is served from cache rather than from spinning disk or flash, achieving the lowest possible latency.

Why the distractors are wrong:

• A. Cache Partition Manager allocates dedicated cache segments to workloads to prevent cache monopolization - it manages how much cache a workload can use, not whether a specific LUN stays resident.
• B. Volume Migration moves data between storage tiers or pools; it's a tiering/relocation tool, not a cache-locking tool.
• D. Data Retention Utility write-protects volumes for compliance and regulatory purposes - it has nothing to do with performance or cache behavior.

Memory tip: Think of the word residency - a resident stays put. Cache Residency Manager keeps your LUN residing permanently in cache, while Cache Partition Manager just sets the boundaries of the neighborhood it can live in.

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