A company plans to add five drives to a 30 drive SAS Flash 4 All-Flash pool on a Dell Unity XT 680 storage array. Which drive type can be used for the expansion?

Question

Options

• ASAS Flash 4
• BSAS Flash 2
• CSAS Flash 3

• A
  93% (25)
• B
  4% (1)
• C
  4% (1)

Explanation

On Dell Unity XT storage arrays, an All-Flash pool must be expanded using the same drive type as the existing drives - a SAS Flash 4 pool can only accept SAS Flash 4 drives, making A the only valid choice.

B (SAS Flash 2) is wrong because Flash 2 drives are an older, slower generation and cannot be mixed into a Flash 4 pool - Dell Unity enforces drive-type homogeneity within a pool tier to maintain consistent performance and data layout.

C (SAS Flash 3) is similarly wrong for the same reason: even though Flash 3 is closer in generation to Flash 4, Unity XT does not permit cross-generation mixing within a single pool.

Memory tip: Think of pool expansion like adding RAM sticks - you can't mix speeds (DDR4 vs DDR5) in the same channel. On Unity XT, "like drives with like drives" is the rule: the pool type in the name tells you exactly which drives can join it.

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