When configuring external storage on a VSP storage system, what happens when the Inflow Control option is set to Enable?

Question

Options

• AWrites will be rejected when the external volume cannot be accessed.
• BWrites will be rejected when the cache usage is above threshold 1.
• CWrites will be accepted when the external volume cannot be accessed.
• DWrites will be rejected when the cache usage is above threshold 2.

• A
  85% (33)
• B
  8% (3)
• C
  3% (1)
• D
  5% (2)

Explanation

Inflow Control = "Stop the flood before the dam breaks."

When Inflow Control is Enabled on a VSP system, the array protects itself by rejecting write I/Os when an external volume is unreachable. Without this safeguard, cache would continue accepting writes with no path to flush them downstream, risking cache overflow and potential data loss - enabling Inflow Control cuts off that risk at the source, making A correct.

Why the distractors are wrong:

• B is wrong because threshold 1 cache usage triggers a different behavior (destaging acceleration), not write rejection tied to external volume availability.
• C is the exact opposite of correct behavior - accepting writes to an unreachable volume is precisely the dangerous condition Inflow Control is designed to prevent.
• D is wrong because threshold 2 cache behavior relates to internal cache pressure management, not the accessibility state of external volumes.

Memory tip: Think of "Inflow Control" literally - it controls the inflow of writes. When the drain (external volume) is blocked, you stop the inflow (reject writes). Enable = protection on; the moment external access fails, the gate closes.

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