how to rescan scsi disk to add new LUN without reboot in rhel

After add new SAN disk to linux system, if you want linux system detect new disk without rebooting system you can execute this command.

for scsi disk
#echo 1 > /sys/class/fc_host/host$host/issue_lip

for fc disk
#echo "- - -" > /sys/class/scsi_host/host$host/scan

you can list your hba wwn in linux by display node_name

#cat /sys/class/fc_host/host$host/node_name

while $host is your hba no.

you can display scsi device in linux system by display scsi that will map to device like /dev/sda, /dev/sdb in sequence.

#cat /proc/scsi/scsi

for example: it will map scsi0 to /dev/sda and scsi1 to /dev/sdb

Host: scsi0 Channel: 00 Id: 00 Lun: 00
Vendor: ATA Model: ST3320620NS Rev: 3.AE
Type: Direct-Access ANSI SCSI revision: 05
Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: ATA Model: ST31000333AS Rev: CC1H
Type: Direct-Access ANSI SCSI revision: 05


to remove single scsi device:

echo "scsi remove-single-device a b c d" > /proc/scsi/scsi

to add single scsi device:

echo "scsi add-single-device a b c d" > /proc/scsi/scsi

while
a == hostadapter id (first one being 0)
b == SCSI channel on hostadapter (first one being 0)
c == ID
d == LUN (first one being 0)