FAIS FlashArray-Implementation-Specialist Reddit Questions

After executing the puredb run giveback --safe command during a manual controller upgrade or specific non-disruptive upgrade (NDU) procedure, the Implementation Engineer must wait for10 minutesbefore proceeding to the next step (typically upgrading the peer controller).

The giveback command instructs the recently upgraded controller (e.g., CT0) to resume its primary role and take back ownership of its assigned storage resources and I/O handling from the peer controller. This process triggers a failover event for the host multipathing software.

Path Stabilization:The 10-minute wait time is a critical safety buffer mandated to ensure that all host-side multipathing drivers (MPIO) have successfully recognized the restored paths to the upgraded controller and have stabilized.

Risk Mitigation:Proceeding too quickly—before the hosts have fully settled and paths are marked as "Active/Optimized"—could lead to an "all paths down" (APD) scenario when the second controller is taken offline for its upgrade. This wait time verifies that the upgraded node is fully functional and carrying load, adhering to the strict "availability first" philosophy of FlashArray upgrades.

The FlashArray//XL features a robust2+2power supply unit (PSU) redundancy configuration. Unlike the smaller FlashArray//X chassis (3U), which typically utilizes two power supplies in a 1+1 redundancy setup, the FlashArray//XL utilizes a larger 5U chassis designed for higher performance and density, requiring a more substantial power infrastructure.

The //XL chassis is equipped with four physical Power Supply Units. These are configured to operate in an N+2 mode (effectively 2+2), meaning the system requires two PSUs to support the full electrical load of the chassis, while the other two provide redundancy. This architecture allows the array to survive the simultaneous failure or loss of input power to up to two power supplies without any interruption to service.

This design ensures maximum availability even in scenarios where an entire power grid feed (A-side or B-side) fails, or if multiple hardware components malfunction simultaneously. Options A (1+1) applies to the standard //X series, and Option C (3+1) is not a supported configuration for the FlashArray//XL. The 2+2 design is critical for maintaining the "Always-On" reliability standards required for the mission-critical workloads that the //XL platform supports.

The FlashArray//XR5 (and //E family) introduces a significant architectural shift regarding Non-Volatile RAM (NVRAM). In previous generations (like R2/R3), NVRAM was provided by dedicated PCIe modules installed in specific "NVB" slots in the chassis.

In the //XR5 architecture, Pure Storage moved toDistributed NVRAM. The NVRAM functionality is integrated directly into the DirectFlash Modules (specifically theDFMDs- DirectFlash Module with Distributed NVRAM). This allows the NVRAM capacity to scale with the storage and removes the bottleneck of dedicated slots.

For a system to function correctly, a minimum number of these NVRAM-equipped modules must be present to form the initial write buffer and system quorum. The standard installation requirement for an //XR5 is that thefirst 10 slots (Slots 0-9)are populated with these specific DFMDs. This ensures there is sufficient distributed NVRAM capacity to boot the Purity operating environment and handle incoming writes safely. The Implementation Engineer must populate these slots first before adding standard DFMs in the remaining slots.

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For a Non-Disruptive Upgrade (NDU) from aFlashArray//Xto aFlashArray//XL, the upgrade kit typically contains4 QSFP cables, 2 Mellanox cards, and 20 DFMD blanks (or modules).

2 Mellanox Cards:The FlashArray//X (source) likely requires the installation of 100GbE RoCE adapters (Mellanox) into its controllers to establish the high-speed replication link with the new FlashArray//XL (which has 100GbE native). One card is installed per //X controller.

4 QSFP Cables:To ensure a redundant, high-bandwidth connection between the two arrays during the data migration phase, 2 cables are used per controller pair (CT0-to-CT0 and CT1-to-CT1), totaling 4 cables.

20 DFMDs (Blanks/Fillers):The FlashArray//X typically holds 20 DirectFlash Modules. The FlashArray//XL chassis has 40 slots. When the 20 data drives are physically moved from the //X to the //XL, the //XL will still have 20 empty slots. These must be filled with DirectFlash blanking modules (DFMD blanks) to maintain proper chassis airflow and thermal pressure. Thus, the kit includes these 20 fillers.