D-PDD-DY-23 practice question 11 of 15

What rule must be followed during an upgrade procedure with the FS25 expansion shelf?

Full set: 91 questions

Answer options

A: If ES40 SAS shelves are on the same chain as an FS25, the maximum number of shelves on that chain is five

B: FS25 shelf must be on the same chain with DS60

C: For high performance, the connections from a controller to FS25 shelves must be over FC cables

D: FS25 shelf is cabled on a separate private chain Correct answer

Correct Answer:

D. FS25 shelf is cabled on a separate private chain

Explanation

The FS25 is an NVMe-based expansion shelf. Due to its different protocol and performance characteristics compared to SAS-based shelves (like ES40 or DS60), it cannot be mixed on the same back-end chain. The architecture requires that FS25 shelves be cabled on their own dedicated private chain, separate from any SAS expansion shelves, to ensure proper functionality and performance.

Why Incorrect

A. FS25 (NVMe) and ES40 (SAS) shelves use different protocols and cannot be on the same chain.
B. FS25 (NVMe) and DS60 (SAS) shelves are incompatible on the same chain for the same reason as option A.
C. The FS25 shelf connects to the controller using PCIe or NVMe-oF technology, not Fibre Channel (FC) cables.

References

1. Dell PowerProtect DD Series Hardware Overview and Installation Guide (for DD6400, DD6900, DD9400, DD9900, and FS25). In the "Cabling the FS25 shelf" section, it states, "The FS25 shelf is cabled on a separate private chain."

2. Dell PowerProtect DD Series Expansion Shelf Hardware Overview (for ES40, DS60, and FS25). The "FS25 shelf" section details its NVMe architecture, which is distinct from the SAS architecture of ES40 and DS60 shelves, precluding them from being on the same chain.

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