During a hardware NDU from a FlashArray//X20R3 to an X20R4-LL (low-line) model, the Implementation Engineer...

When performing a Hardware Non-Disruptive Upgrade (HWNDU) to the FlashArray//XR4 generation, Implementation Engineers must be acutely aware of power constraints. The //XR4 architecture introduced massive performance upgrades, leveraging PCIe Gen4 and newer Intel processors. Consequently, standard //XR4 arrays strictly require high-line power (200V-240V) to operate.

However, to accommodate entry-level customers in smaller datacenters or edge locations, Pure Storage released the //X10R4-LL and //X20R4-LL ("Low-Line") models. These specific models are equipped with power supplies designed to run on standard 120V circuits.

The critical tradeoff for using 120V low-line power is a strict physical limitation on available wattage. Because 120V circuits cannot deliver the peak wattage required to spin up a fully populated chassis while driving the Gen4 compute overhead, the //X10R4-LL and //X20R4-LL strictly support a maximum of 10 capacity drives (a single data pack) in the chassis.

If an Implementation Engineer is upgrading an older //X20R3 that had 20 drives (which was previously supported on low-line power due to lower CPU overheads) to an //X20R4-LL, the pre-flight power supply validation script will intentionally fail. The array detects that the 120V supplies cannot safely support the 20 physical drives currently seated in the chassis. To resolve this, the customer must either provide 208V+ high-line power and use standard R4 power supplies, or migrate the excess capacity to an external DirectFlash Shelf (which has its own independent power).