H13-624: HCIP-Storage V5.5Demo

By Huawei · Question Mode

QuestionQ10

Overview of ModelArts

Cache policies and configurations contribute to storage-layer performance optimization for Huawei flash storage. Which statement about a cache’s high and low watermarks is false?

  • A Generally, the high watermark of the cache should not be too high, and the difference between the high and low watermarks should not be too small.
  • B If the high watermark of the cache is too high, I/O fluctuation and latency increase will occur usually when the current I/O traffic bursts.
  • C Generally, the low watermark for storing dirty data in the cache should not be too low. The recommended value is 20%.
  • D If the high watermark of the cache is too high, the write performance will be affected. If the low watermark of the cache is too low, read performance will be affected.
Explanation

A high watermark that is set too high leaves insufficient cache-buffer space; burst I/O can therefore produce I/O fluctuations and higher latency, affecting write performance. A low watermark set too low causes dirty cached data to be flushed to disks too frequently, which degrades write performance rather than read performance. Huawei recommends a 20% low watermark and adequate spacing between the high and low watermarks.

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