S2600 link Brocade 200E switch with FC port. IBM3650 server link S2600 via FC switch, 3650 system is LINUX AS4. And server find the mapped 2T LUN.
The server install completely and reset. But the server cannot start again, it remind that start position is not right, you must boot with floppy disk.
IBM engineer modifies disk ID and start server successfully.
Pull out optical fiber and start again, the server can enter into system successfully, then cut in fiber and find lun. But booting with fiber is always failed. Then we cooperate with IBM engineer and find that mapped lun take over logical hard disk ID, so it is booting from lun. The reason is clear.
It is small-probability event. This case has relation with server and HBA card drivers. Via experiment it is not existing on the same type server. Fault server recover after using other type HBA card. So we can solve this problem with replacing HBA card or modify disk ID.