multipath on linux - how the disk look like

modprobe -l | grep the "driver desc"

if not there, install it...
ex. go to brocade, download, install with some options like --update-initrd

after this the /sys/class/fc_host folder is there

after you scanning with
echo "1" > ............./issue_lip
echo "- - -" > ................../scan

the device will appear in proc/scsi/scsi file.

when you part it, you need to restart it:
ex. dm-2 will have dm-2p1 as partition 1, but you can not format it untill you reboot it, it will add another disk called dm-3 whcih is same with dm-2p1.

RHEL 4 does not have yum

You can either install it manually with some deps packages, or just use GUI :
system-config-application --isodir=/isoFolder

useful also when u have no CDRom