After you add a new disk on a Red Hat Linux server you can scan for the new disk without rebooting.
List the number of scsi host controllers
ls /sys/class/scsi_host
host0 host1 host2
Run this command to to scan each host0, host1 and host2
echo “- – -” /sysc/class/scsi_host/host0
Alternatively you can do all the above with this one line script
ls /sys/class/scsi_host/ | while read host; do echo “- – -“> /sys/class/scsi_host/$host/scan; done