Exam FlashArray-Storage-Professional Topic 4 Question 67 Discussion

Understanding CRC Errors: CRC (Cyclic Redundancy Check) errors occur when the data received at a port does not match the checksum sent by the initiator or switch. In a Pure Storage environment, these are tracked per port and can be viewed via the CLI (purehw list) or the GUI.
Configuration vs. Hardware: While a failing SFP or a damaged fiber cable can cause CRC errors, they are a primary indicator of configuration mismatches in the SAN fabric. Common culprits include:
Port Speed Mismatches: Manually setting a port to 16Gbps when the switch is set to "Auto" or 8Gbps.
Duplex Mismatches: Though rare in modern Fibre Channel, it is a classic Ethernet/iSCSI configuration error.
MTU Mismatches: In iSCSI or NVMe-oF environments, if the FlashArray is configured for Jumbo Frames (MTU 9000) but the switch or host is at MTU 1500, packet fragmentation or CRC-like errors/drops will occur.
Why Option A is incorrect: A blinking status LED on a controller is often part of normal operation (indicating heartbeat or activity). A solid amber LED would be an indicator of a hardware failure, not necessarily a misconfiguration.
Why Option C is incorrect: While latency spikes can be caused by misconfiguration (like incorrect MPIO settings), they are more commonly symptoms of workload changes, "noisy neighbors," or reaching the physical performance limits of the array. CRC errors are a much more specific diagnostic "smoking gun" for port and fabric configuration issues.
Best Practice: When CRC errors are detected, Pure Storage recommends first checking the physical layer (reseating SFPs/cables) and then verifying that the port speed and protocol settings on the FlashArray match the upstream switch configuration exactly.