How do I find the FC ID (WWN) of a disk/LUN on Linux server?

If your server is connected to more than two SANs of the same type it is really hard to find what disk is on what SAN and how it is connected to your server. You can get the Fiber Channel addresses of the HBAs by typing the following commands:
# systool -c fc_host -v
Type the following command to determine the fibre channel target WWN:
# systool -c fc_transport -v
You will get node name (FC WWN) and port name of the storage processor port. Type the following command, to determine the mapping between SCSI HBTL addresses and the disks:
# sg_map -x
See sg_map and systool command man page for more details.