====== Rescan SCSI bus ======

There is no need to reboot in order to rescan SCSI/FC bus

Rescan SCSI bus
  echo "- - -" > /sys/class/scsi_host/host<#>/scan
  
If many hosts exists take them in one go:
   for hosts in  /sys/class/scsi_host/*; do echo "- - -" > $hosts/scan ; done  

====== Rescan FC bus ======

  echo "1" > /sys/class/fc_host/host#/issue_lip

If several hosts exists take them in one go:
  for hosts in /sys/class/fc_host/*; do echo "1" > $hosts/issue_lip; done

====== LUN/Disk expansion ======
  
Expand Vmware disk / SAN LUN.

Force rescan to get the kernel aware of the new size (supposing your LUN is /dev/sdb):

  # echo 1 > /sys/block/sdb/device/rescan

In case multipathing is beeing used, the command has to been issued on all devices. eg. sdc/sde etc. multipath -ll can be used to list the devices.