Authentic Pure Storage Certification Exam FlashArray-Storage-Professional Questions Answers

On a Pure Storage FlashArray, Ethernet ports operate at both a physical hardware layer and a logical network configuration layer. If you need to verify the actual physical negotiated port speed of an Ethernet port (for example, verifying if a 25GbE port negotiated down to 10GbE due to switch configurations or cable limitations), you must query the hardware layer directly.

The command purehw list --all --type eth interacts directly with the physical NIC hardware components to report their true link status, health, and dynamically negotiated hardware link speed.

Here is why the other options are incorrect:

purenetwork eth list -- all (B): The purenetwork command suite is primarily focused on the logical Layer 2/Layer 3 networking stack. It is used to configure and list IP addresses, subnet masks, MTU sizes (Jumbo Frames), and routing, rather than focusing on the physical hardware negotiation details of the NIC itself.

pureport list (A): The pureport command suite is specifically used for managing and viewing storage protocol target ports. An administrator would use this to list the array ' s Fibre Channel WWNs or iSCSI IQNs to configure host zoning or initiator connections, not to verify Ethernet link negotiation speeds.

Requirement for Lossless Ethernet: NVMe over RoCE (RDMA over Converged Ethernet) requires a lossless fabric to function correctly. Unlike standard iSCSI which uses TCP for error recovery, RoCE assumes the network will not drop packets. If the network is " lossy, " performance degrades significantly.

The Role of PFC: Priority Flow Control (PFC) (IEEE 802.1Qbb) is the specific mechanism used in Data Center Bridging (DCB) to provide flow control on a per-priority basis. It allows the switch to send a " pause " frame to the sender when buffers are full, preventing packet drops.

Symptom Analysis: In the scenario provided, the array itself is not overloaded ( " within the performance envelope " ). However, the addition of a new workload increased traffic to the point where buffer congestion occurred. Because PFC was likely misconfigured (either on the FlashArray ports, the network switches, or the host NICs), the network dropped packets instead of pausing traffic. This leads to " go-back-N " retransmissions and massive latency spikes that affect all workloads sharing that fabric.

Pure Storage Best Practices: Pure Storage documentation for NVMe-RoCE emphasizes that PFC must be enabled and consistent across the entire path. If there is a mismatch in PFC configuration, the resulting packet loss will cause the symptoms described: extreme latency and potential service outages.

The ActiveCluster Mediator (whether it is the Pure1 Cloud Mediator or the On-Premises VM) is a lightweight tie-breaker that communicates continuously with the management interfaces of both FlashArrays. If it was previously online and suddenly reports as " unreachable " from both arrays simultaneously, the issue is almost always caused by a network interruption or firewall rule change blocking the required communication ports between the arrays ' management IP addresses and the Mediator VM.

If a network firewall is suddenly configured to drop or deny outbound TCP traffic (such as port 80/443 depending on the specific HTTP/HTTPS discovery and heartbeat configuration) from the FlashArrays to the ESXi-hosted Mediator, the arrays will fail to send their heartbeats, causing the mediator status to drop to " unreachable. "

Here is why the other options are incorrect:

Fibre Channel (FC) zoning or network access has not been created properly for the host (A): The Mediator is completely independent of the front-end host storage fabric (Fibre Channel or iSCSI). Host zoning issues would prevent the ESXi server from seeing its volumes, but it would not cause the FlashArrays to lose management network connectivity to the Mediator.

The mediator does not reside within a Pure datastore (B): This is actually a strict best practice and requirement . Pure Storage explicitly states that the On-Premises Mediator VM must be deployed in a separate (third) failure domain. It should not reside on the ActiveCluster mirrored datastore, because a site-wide SAN failure would take the mediator offline exactly when it is needed most. Therefore, not residing on a Pure datastore is the correct setup, not a cause for an outage.