Rescan LUN's without rebooting RedHat 6 /Cent OS

# ls /sys/class/fc_host
 host0  host1  host2  host3

#echo "c t l" >  /sys/class/scsi_host/hostH/scan

where H is the HBA number, c is the channel on the HBA, t is the SCSI target ID, and l is the LUN.