A financial customer purchases a Huawei flash storage device for subsequent service deployment. During storage configuration, an administrator finds that LUNs mapped to an application server cannot be detected on the application server. Which of the following are possible causes of this exception?

If LUNs mapped to a server are not detected, several issues could be the cause. Among the options, B and C are valid potential causes. Some older operating systems, notably HP-UX, require a LUN with Host LUN ID 0 to be mapped from a target before they can successfully scan for and discover other LUNs from that same target. Additionally, on UNIX/Linux systems, if the device node file (e.g., /dev/sdc) is accidentally deleted, the application server's operating system will lose its handle to the device, making it seem undetectable until a bus rescan recreates the file.

A. A faulty storage pool would typically make a LUN faulty or offline, but the LUN object itself might still be visible in the mapping view. The primary issue is LUN detection on the host, which is more related to the host-storage path and host configuration.
D. Serial port connection parameters are for out-of-band command-line interface (CLI) management of the storage controller. This connection is entirely separate from the data path (Fibre Channel or iSCSI) used for LUN discovery and I/O.

1. Huawei OceanStor Dorado V6 Host Connectivity Guide for HP-UX, "Connecting to Storage Systems". The guide specifies compatibility requirements and notes that for some configurations, "the host LUN ID of the first LUN mapped to an HP-UX host must be 0." (Section: Pre-Configuration Checklist).

2. Huawei OceanStor Dorado V6 Troubleshooting Guide, "Host Connectivity Faults > A Host Fails to Discover LUNs". The guide lists common causes, including incorrect host configuration, zoning issues, and the need to perform a host bus rescan. The loss of a device file necessitates a rescan to be "detected" again by the OS file system.