nerdexam
Dell-EMC

D-UN-OE-23 · Question #24

A system administrator wants to limit I/O for the following LUNs: - LUN A: Size 100 GB, Limit:500 IOPS - LUN B: Size 500 GB, Limit: 1000 1OPS - LUN C: Size 500 GB, Limit: 500 1OPS - LUN D: Size 1000…

The correct answer is B. Two absolute limit policies. Option B is correct because the four LUNs can be grouped by their absolute IOPS limits into exactly two groups: a 500 IOPS policy covering LUN A and LUN C, and a 1000 IOPS policy covering LUN B and LUN D. An absolute limit policy caps I/O at a fixed value regardless of LUN…

Unity Management and Monitoring

Question

A system administrator wants to limit I/O for the following LUNs:

  • LUN A: Size 100 GB, Limit:500 IOPS
  • LUN B: Size 500 GB, Limit: 1000 1OPS
  • LUN C: Size 500 GB, Limit: 500 1OPS
  • LUN D: Size 1000 GB, Limit: 1000 1OPS

What type and number of host I/O limit policies must be used?

Options

  • AOne shared absolute limit policy
  • BTwo absolute limit policies
  • COne absolute policy and one density based limit policy
  • DTwo density based limit policies

How the community answered

(31 responses)
  • A
    6% (2)
  • B
    55% (17)
  • C
    10% (3)
  • D
    29% (9)

Explanation

Option B is correct because the four LUNs can be grouped by their absolute IOPS limits into exactly two groups: a 500 IOPS policy covering LUN A and LUN C, and a 1000 IOPS policy covering LUN B and LUN D. An absolute limit policy caps I/O at a fixed value regardless of LUN size, making this the simplest and most efficient solution here.

Why the distractors fail:

  • A (One shared absolute policy) is wrong because the LUNs have two distinct IOPS ceilings (500 and 1000), so no single absolute limit policy can satisfy all four requirements simultaneously.
  • C (One absolute + one density-based) is unnecessary complexity - mixing policy types is only warranted when the limits scale with LUN size, which isn't required here.
  • D (Two density-based policies) fails because density-based limits are expressed as IOPS-per-GB. Computing the densities (LUN A = 5 IOPS/GB, B = 2 IOPS/GB, C = 1 IOPS/GB, D = 1 IOPS/GB) reveals three distinct densities, so you'd need at least three policies - not two.

Memory tip: Ask yourself "do the limits scale with size?" If yes → density-based. If no → absolute. Then count how many unique limit values exist - that tells you the minimum number of policies needed. Here, two unique absolute values (500 and 1000 IOPS) → two absolute policies.

Topics

#host I/O limits#absolute limit policy#QoS#IOPS

Community Discussion

No community discussion yet for this question.

Full D-UN-OE-23 Practice