FAIS FlashArray-Implementation-Specialist Updated Exam

The command to check I/O health and validate connectivity after a controller upgrade is purehost monitor --balance .

Following an upgrade (especially after a controller reboot or failover/giveback), it is essential to verify that the host Multipath I/O (MPIO) drivers have re-established connectivity to all paths.

purehost monitor : Displays real-time performance statistics (IOPS, Bandwidth, Latency) for connected hosts.

--balance : This specific flag breaks down the metrics per initiator (HBA port) for each host.

Why it's used: An Implementation Engineer uses this to look for "imbalanced" flow. If one initiator shows high IOPS and another shows zero, it indicates a dead path, a zoning issue, or an MPIO driver that failed to recover the path to the upgraded controller. Options A and B provide static configuration lists (mappings and WWNs) but do not show live I/O flow, making them insufficient for health monitoring.

To determine the specific model of a replacement controller while in the puresetup or manufacturing shell (before the controller has joined the cluster), the correct command is hwconfig --model .

During a controller replacement procedure, the engineer often connects to the new controller via serial or a temporary IP. At this stage, the full Purity CLI (and thus purearray list) may not be fully available or relevant because the controller is in a "setup" or "unconfigured" state.

hwconfig : This is a lower-level utility used to read the Field Replaceable Unit (FRU) data directly from the hardware VPD (Vital Product Data).

--model : This flag specifically filters the output to display the model string (e.g., FA-X50R3-CT0). Verifying this string is a critical safety step to ensure the replacement hardware matches the existing cluster node before attempting the software join process (puresetup replace).

The FlashArray//XL series (such as the XL130R5) utilizes a modern backend connectivity architecture for its expansion shelves, specifically the DirectFlash Shelf (DFS). Unlike older generations that might have used SAS (Serial Attached SCSI) for shelf connectivity, the //XL architecture relies on high-speed Ethernet with RoCE (RDMA over Converged Ethernet) to communicate with external media shelves. This ensures that the NVMe drives in the shelf perform with the same low latency as those in the head unit.

To attach a DirectFlash Shelf to a FlashArray//XL130R5, the chassis must be populated with specific PCIe interface cards designated for shelf back-end connectivity. The correct part for this is the FA-XL-100G Ethernet/RoCE 2-Port card. This card provides the necessary 100 Gigabit Ethernet bandwidth and RoCE protocol support required for the NVMe-oF (NVMe over Fabrics) backend fabric that Pure Storage uses.

It is crucial to distinguish this from host-facing cards. While an "iSCSI/RoCE" card exists, the shelf connectivity specifically utilizes the "Ethernet/RoCE" designation in the BOM to differentiate backend fabric ports from frontend host ports. The 200G options are generally reserved for host connectivity or inter-array clustering in specific high-performance setups, but the standard validated card for connecting the DFS to the //XL130R5 is the 100G Ethernet/RoCE adapter. Verifying this line item on the BOM prevents onsite delays where the engineer might otherwise find themselves with incompatible ports for the expansion shelves.

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."

=========