To issue a SCSI bus rescan you must know on which bus you’ve added the device. If you don’t know which bus and if there are mutliple buses on the system you can rescan each bus which will be somehow annoying but will not interrupt the system.
To initiate a SCSI bus rescan type:
root# echo "- - -" > /sys/class/scsi_host/hostX/scan
where X stands for the SCSI bus you want to scan, and then you can type the following:
root# fdisk -l
root# tail -f /var/log/message
Also C T L “Channel on HBA” “Tatget SCSI id” “LUN” can be used instead of “—“.