The Pure Storage FlashArray//XL platform, which includes the //XL130 and //XL170 models, is engineered to support a maximum of four DirectFlash Shelves (DFS). This configuration allows for substantial capacity scaling beyond the main chassis. The system's architecture, including its NVMe-oF RoCE interconnects, is designed to maintain high performance and low latency even when fully expanded with the maximum number of shelves. This scalability is a key feature of the //XL line, targeting large-scale, mission-critical enterprise workloads.

A. 2: This is an incorrect limit. The FlashArray//XL platform is designed to scale beyond two shelves to meet higher capacity demands.

B. 3: This represents a valid, but not maximum, configuration. The system can support an additional shelf beyond this number.

1. Pure Storage, Inc. (2023). FlashArray//XL Family Data Sheet. Page 2, "SPECIFICATIONS" table, row "Max Shelves". The value listed for both FlashArray//XL130 and FlashArray//XL170 is 4.

2. Pure Storage, Inc. (2023). FlashArray//X and //XL Installation and Upgrade Guide. Document Purity//FA 6.x.x, Rev L. Section: "Cabling Diagrams for FlashArray//X and //XL", sub-section "Cabling a FlashArray//XL with Four Shelves". This section provides the official cabling diagram and procedure for the maximum supported configuration, confirming it is four shelves.