Rescan a SCSI bus without rebooting

Normally, after adding a hotplug-capable HDD to Linux (on a VM or physical machine), running:

# fdisk -l

does not show the HDD until the machine is rebooted. To have Linux detect the new HDD without rebooting, rescan SCSI. To scan SCSI:

1. ตรวจสอบจำนวน scsi controller
   # ls /sys/class/scsi_host
   host0 host1 host2

2. Based on the output above, rescan host0, host1, and host2 by running the following commands.

   # echo "- - -" > /sys/class/scsi_host/host0/scan
   # echo "- - -" > /sys/class/scsi_host/host1/scan
   # echo "- - -" > /sys/class/scsi_host/host2/scan

English reading note: The Thai line in the first preserved example means “Check the number of SCSI controllers.” The example lists host0, host1, and host2.