CentOS / Debian: detect a new disk / lun without rebooting linux

Particularly under VMware you may just add a new disk to linux without the need to reboot the whole thingy. So after adding the new disk as root on the OS:

echo "- - -" > /sys/class/scsi_host/host#/scan

where host# is the bus address usually 0 example

echo "- - -" > /sys/class/scsi_host/host0/scan

fdisk -l

will show you the new disk as unpartioned while you would expect to see a message in the messages log

tail -f /var/log/message

and thats it, you now have a new disk which you can partition and add to LVM or whatever you want with it.