Red Hat Enterprise Linux reports lunXXX has a LUN larger than allowed by the host adapter, where XXX is a very large number

Issue

• Can not see the LUNs presented from the SAN
• Disks paths with LUN numbers > 255 are not found.
• Unexpected entries with LUN numbers between 16384-32767 are found
• Unexpected entries with LUN numbers greater than 65536, commonly 4194304 or larger are reported by the kernel.
• Getting error message of either:
  • "scsi: host 0 channel 0 id 2 lun16643 has a LUN larger than allowed by the host adapter", or
  • "scsi: host 2 channel 0 id 0 lun4194304 has a LUN larger than allowed by the host adapter"
• Tried setting lpfc_max_luns to 4200000 and get:
  • "scsi_report_lun_scan: Allocation failure during SCSI scanning, some SCSI devices might not be configured"
• Why does the kernel remap storage LUN 256 to 16640 when scsi LUN address method 01b is used by storage
  • Will a patch/fix be developed to interpret a large LUN number (>255) in SCSI 01b LUN address format, that is display LUN as 256 and not as 16640.
• Why does the LUN (logical unit number) as reported in storage differ from the LUN address value as reported by the linux kernel?
• Why does linux require a workaround fix of increasing the driver maximum LUN to a large value to support LUNs greater than 256?
• Is there a method to display the LUN id separate from the LUN addressing method employed by storage?
• My storage vendor has tried changing lun access method, but the problem persists.