You plan to disable automatic tier relocation of certain HDT volumes in Hitachi Dynamic Tiering. What are two valid reasons for doing this? (Choose two.)

Question

Options

• ATo ensure prioritization of a volume whose I/O activity is constant.
• BTo ensure prioritization of a volume whose size is growing exponentially.
• CTo ensure prioritization of a volume whose I/O activity varies greatly.
• DTo ensure prioritization of a critical volume whose I/O workload is low.

• A
  9% (3)
• B
  6% (2)
• C
  85% (29)

Explanation

Disabling automatic tier relocation protects volumes that HDT's algorithm would misclassify. A volume with highly variable I/O (C) risks being demoted to a slower tier during quiet periods, then suffering poor performance when activity spikes again - the algorithm can't distinguish a temporary lull from genuine low demand. A critical but low-workload volume (D) will naturally attract little attention from the tiering algorithm and get pushed to slower storage, creating a performance gap exactly when that volume matters most.

Why A is wrong: A volume with constant I/O will consistently be recognized as active by HDT and kept on the appropriate high-performance tier automatically - no intervention needed.

Why B is wrong: HDT relocates data based on I/O activity patterns, not volume size. Exponential growth in capacity has no bearing on how the tiering algorithm scores or moves data.

Memory tip: Think of it as protecting "problem children" of the algorithm - volumes with unpredictable patterns (C) and sleeping giants that are critical but quiet (D). If HDT can read a volume correctly (steady I/O like A), let it work; if size is the issue (B), that's a provisioning problem, not a tiering one.

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