An Implementation Engineer is upgrading a FlashArray//X50R3 to an //X50R4.

When performing a controller upgrade (Non-Disruptive Upgrade) from an //X50R3 to an //X50R4, the specific hardware configuration of the source array dictates the target bill of materials. The presence of SAS drives in the chassis indicates that the source is a legacy or transitional configuration, as the standard //X R4 platform is optimized for end-to-end NVMe (DirectFlash).

However, the question asks for the specific controller SKU required. In Pure Storage nomenclature for upgrades, the standard controller replacement part is typically the base model code, here FLASHARRAY//XC50 R4 .

The "XC" designation often refers to the controller component itself in upgrade kits. While special considerations apply to SAS media (which are usually phased out or require specific handling during R4 upgrades since R4 natively drops legacy SAS support on the motherboard), the controller part number itself remains the standard R4 SKU (Option C). Options like "SE" or "NS" (often denoting specific encryption or networking variants) are not the standard identifiers for the base controller upgrade in this context.

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