Pure Storage Pure Certified FlashArray Implementation Specialist (FAIS) Exam FlashArray-Implementation-Specialist Exam Dumps: Updated Questions & Answers (March 2026)

The FlashArray//X70 (R2/R3) and FlashArray//X90 (R2/R3) require 1600W Power Supply Units (PSUs) .

Pure Storage equips its FlashArray//X chassis with different power supply capacities based on the compute load of the installed controllers:

Performance Tier (X70/X90): These models utilize high-core-count Intel Xeon processors and support the maximum density of NVMe DirectFlash Modules. To support the peak power draw of these components while maintaining N+1 redundancy (where one PSU can support the entire load), the 1600W units are mandatory.

Entry/Mid Tier (X10/X20/X50): Lower-end models often ship with 1000W or 1200W PSUs (though X50 often uses 1600W in later revisions or specific configs).

Identification: Implementation Engineers can identify these PSUs by the label on the rear handle (often color-coded or explicitly marked "1600W"). Installing an X90 controller into a chassis with older 1200W PSUs (e.g., during an improper upgrade attempt) would likely trigger a hardware alert or prevent the controllers from booting due to insufficient power budget.

After a controller upgrade or any maintenance that involves path failovers, it is critical to verify that the host multipathing software has restored connectivity to all paths and that I/O is being distributed correctly. The specific command to validate this in Purity is purehost monitor --balance .

purehost monitor --balance : This command provides a real-time view of I/O statistics per initiator (host path). It highlights imbalances where one path might be taking zero traffic while others are overloaded, which typically indicates a pathing configuration issue, a bad cable, or a host that has not correctly rediscovered the path after the controller reboot.

purehost list simply displays configured hosts, not live performance data.

pureport list displays the status of array ports but does not show the per-host I/O distribution required to verify "balance."

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The Purity upgrade process involves two main phases: installing the software image (placing the bits on the boot drive) and then activating it (booting into the new kernel).

After the pureinstall command has successfully unpacked and staged the new Purity version, the changes are not live until the system reboots. In a Non-Disruptive Upgrade (NDU), this is done one controller at a time.

The required step to commit and run the new version is to Reboot the controller .

The pureinstall workflow typically prompts for or automatically initiates this reboot.

The secondary controller reboots first, loads the new Purity version, and rejoins the cluster.

Then, the primary controller fails over services to the updated secondary, reboots, and updates itself.

A full "Reboot the array" (simultaneous reboot) would be disruptive and is not the standard procedure for an NDU. "Logging out" has no effect on the system state.

Understanding the hardware architecture and proper drive population rules is critical during a Pure Storage FlashArray installation. FlashArray models generally utilize either standard DirectFlash Modules (DFMs) or DirectFlash Modules with distributed NVRAM (DFMDs).

DFMDs, primarily introduced with models like the FlashArray//XL, integrate non-volatile write caching directly into the capacity drives themselves, eliminating the need for dedicated NVRAM hardware modules. However, standard FlashArray models—such as the //X10, //X20, //X50, //X70, and //X90—use standard DFMs strictly for capacity. Because standard DFMs do not contain built-in NVRAM, these arrays rely heavily on specialized, dedicated NVRAM modules to safely acknowledge incoming writes and protect data in flight against unexpected power loss or controller failures.

To maintain absolute high availability and guarantee there is no single point of failure within the write cache, NVRAM is always mirrored across two separate physical modules. During the physical hardware installation of a non-DFMD array, the Implementation Engineer must populate the dedicated NVRAM bays located centrally on the chassis. According to official Pure Storage implementation guidelines, the primary pair of NVRAM modules must always be installed in the first two designated bays, which are explicitly labeled NVB0 and NVB1. Placing the modules in alternate or staggered bays (such as NVB0 and NVB2) violates the strict hardware population rules and will prevent the array from initializing.

The FlashArray//E connects to its DirectFlash Shelves (DFS) using 25Gb Ethernet (RoCE) .

The FlashArray//E is the "Capacity Optimized" member of the FlashArray family, designed to replace spinning disk repositories with all-flash efficiency. While the high-performance FlashArray//XL utilizes 100GbE for its backend NVMe-oF connectivity to maximize throughput for mission-critical databases, the //E prioritizes cost-efficiency, density, and power consumption.

Architecture: To maintain this efficiency balance, the backend connectivity for expansion shelves on the //E platform is standardized on 25GbE . This provides ample bandwidth for the QLC-based workloads (typically unstructured data, repository, or Tier 2 block) without the higher cost and power draw of 100GbE optics and controllers.

Comparison: Option A (40G) is a legacy QSFP standard not used in modern Pure backend designs. Option C (100G) is reserved for the performance-tier //XL and high-end //X models.

The upgrade from a FlashArray//XR4 to a FlashArray//XL is a specific "Data-in-Place" hardware migration that utilizes the purewes (Pure Workflow Execution Service) utility to orchestrate complex steps. One of the most critical steps involves stopping the Purity software stack on the controller that is about to be removed (CT0) to ensure a clean failover and data flush to the surviving controller.

The correct command syntax is purewes controller disable --purity --verify-mode secondary --verify-array ARRAY_NAME ct0 .

purewes controller disable : Initiates the shutdown of the controller's services.

--purity : Specifies that the Purity software stack should be stopped (not just the hardware).

--verify-mode secondary : This is a crucial safety check. It ensures the command only executes if CT0 is currently the Secondary controller. If CT0 were Primary, running this command without a failover first would cause an outage.

--verify-array : Confirms the action is being taken on the correct target array.

This command sequence ensures the controller is safely quiesced before the Implementation Engineer physically removes it from the chassis.

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When executing a cross-generational Hardware Non-Disruptive Upgrade (HWNDU) for a customer who has been with Pure Storage for several years, an Implementation Engineer will often encounter legacy storage media. Early generations of the FlashArray relied on SAS-based Solid State Drives (SSDs) before the industry entirely shifted to the much faster NVMe protocol (DirectFlash Modules).

Pure Storage is famous for its Evergreen architecture, which allows customers to upgrade their controllers without having to rip and replace their existing drives. However, a standard modern //XR4 controller natively communicates strictly via NVMe and PCIe lanes. If a customer is upgrading an array that still contains legacy SAS drives (in this scenario, 10 SAS drives mixed with 10 NVMe drives), a standard NVMe-only controller will not be able to read the SAS media, leading to immediate data unavailability.

To solve this, Pure Storage manufactures specific controller configurations. The SE (SAS-Enabled) controller models are explicitly designed with the necessary internal SAS Host Bus Adapters (HBAs) and routing logic to support legacy SAS media alongside modern NVMe drives. Conversely, the NS (Non-SAS) controllers strictly support NVMe media. Because this specific chassis still houses 10 SAS modules, the Implementation Engineer must verify that the Bill of Materials (BOM) shipped for the upgrade is explicitly the "FLASHARRAY//X50 R4, SE" variant to ensure a safe, non-disruptive migration.

When expanding capacity on a Pure Storage FlashArray, it is critical to understand the distinction between normal drive insertion states and hardware fault states. As established in previous deployment steps, when a standard, supported DirectFlash Module (DFM) is inserted into a healthy array, it typically enters an "unadmitted" state. This means the hardware is fully recognized, but the system is securely waiting for the administrator to manually claim the drives using puredrive admit.

However, if an Implementation Engineer inserts a new data pack and the puredrive list command reports the status strictly as "unrecognized," this indicates a deeper software-to-hardware mismatch.

The Purity//FA operating system relies on an internal hardware dictionary (including specific drivers and firmware profiles) to communicate with the custom NVMe flash modules. If a customer purchases a newly released, next-generation DFM (for example, a higher-density QLC drive or a newly manufactured DFM with an updated internal NAND controller), an older version of Purity simply will not know how to interact with it. Because the older OS lacks the required hardware definitions, it flags the drive as "unrecognized." To resolve this issue and proceed with the capacity expansion, the Implementation Engineer must first perform a non-disruptive upgrade of the Purity operating system to a version that officially supports the new drive's Bill of Materials (BOM).

Pure Fusion is a storage-as-code platform that aggregates multiple physical FlashArrays into a single logical "fleet" or cloud-like storage pool. A fundamental rule of the Fusion architecture and registration process is that a specific physical FlashArray can only belong to one Fusion fleet at a time. This exclusivity ensures that the management plane (Fusion) has authoritative control over the resources, placement logic, and workload balancing for that array without conflict from another management entity.

When an Implementation Engineer encounters an error adding an array that is otherwise healthy and successfully connected to the Pure1 cloud (which acts as the mediator for Fusion), the most probable cause is that the array remains registered to a previous or different Fusion fleet. This often happens if an array was used in a proof-of-concept (POC), a lab environment, or a previous deployment and was not cleanly deregistered before attempting to add it to the new production fleet.

To resolve this, the engineer must verify the array's registration status in Pure1 or the Fusion control plane. The array must be explicitly removed or deregistered from the conflicting fleet before it becomes available for claim by the new fleet. While Purity versions are important for compatibility, Fusion supports a range of versions, making "not running the latest " a less likely hard-stop error compared to the binary conflict of existing ownership. Similarly, existing workloads do not prevent an array from joining a fleet; Fusion can often import or manage existing resources depending on the configuration.

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DirectMemory Modules (DMMs) are Storage Class Memory (SCM) drives used in FlashArrays to provide a high-speed read cache (DirectMemory Cache). In the FlashArray//XL architecture, these modules provide significant performance benefits for read-intensive workloads.

A fundamental configuration rule for DMMs on the //XL platform is that they cannot be installed in a DirectFlash Shelf (DFS) .

DMMs must be installed directly into the controller chassis (the head unit) to leverage the lowest possible latency connection to the CPU and memory complex.

The external backend fabric that connects to the shelves (even though it is NVMe-oF/RoCE) adds a minute amount of latency that negates the extreme speed advantage of SCM. Therefore, Purity only supports DMMs when they are local to the controllers.

DMMs share the same physical form factor and slots as standard DirectFlash Modules (DFMs) in the chassis but are typically prioritized for specific slot ranges (e.g., the first few slots) for thermal and bus management.

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