What is the maximum number of DirectFlash Shelves supported for FlashArray//XL?

TheFlashArray//XLcurrently supports a maximum of2 DirectFlash Shelves (DFS).

The FlashArray//XL is a high-density, performance-optimized platform housed in a 5U chassis.

Rack Unit Math:According to the FlashArray//XL specifications and site planning guide, the system supports a maximum configuration footprint of11 Rack Units (11U).

The base controller chassis occupies5U.

Each DirectFlash Shelf occupies3U.

Therefore: 5U (Base) + 3U (Shelf 1) + 3U (Shelf 2) =11U.

Capacity:Because the //XL chassis itself holds 40 DirectFlash Modules (compared to 20 in a standard //X), and each shelf holds 28 modules, a fully populated system with two shelves provides nearly 100 drives of capacity (40 + 28 + 28 = 96 drives). This massive density reduces the need for "daisy-chaining" large numbers of shelves like legacy SAS architectures. Adding a third shelf would push the total height to 14U, exceeding the current platform definition.