On a server with intensive sequential I/O profile, you have set Extended Round Robin within Hitachi Dynamic Link Manager. Which two benefits result from implementing this algorithm? (Choose two.)

Question

Options

• Atracks preloaded to cache
• Bblocks held permanent in Read Cache
• Cno tracks preloading on the system
• Defficient cache usage on the storage system

• A
  79% (26)
• B
  15% (5)
• C
  6% (2)

Explanation

Extended Round Robin is Hitachi's load balancing algorithm optimized for sequential I/O, where reads follow a predictable pattern. Because the algorithm keeps I/O on the same path long enough for the storage controller to recognize the sequential pattern, the array's prefetch engine proactively preloads tracks into cache (A) before they are requested - eliminating wait time. This prefetch behavior directly produces efficient cache usage (D), since cache lines are filled with data that will actually be needed, maximizing hit rates and reducing physical disk reads.

Why C is wrong: "No tracks preloading" is the exact opposite of what Extended Round Robin achieves - preloading is its core advantage for sequential workloads.

Why B is wrong: Permanently holding blocks in Read Cache is not a feature of any HDLM algorithm; it would waste cache space and is not how storage prefetch works.

Memory tip: Think "Extended = Exploit sequential patterns." Sequential I/O is predictable, so Extended Round Robin lets the storage array predict ahead - preloading tracks (A) and using cache smartly (D). If an answer implies cache is wasted or prefetch is disabled, it contradicts the whole point of the algorithm.

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