udev Rules for the Hard drives..
Use udevinfo to get unique attributes about the devices you are going to write a rule for.
udevinfo -a -p /sys/block/sda | grep -i model
Gives the following output: SYSFS{model}="LD 0 RAID1 139G"
udevinfo -a -p /sys/block/sda | grep -i size
Gives the following output: SYSFS{size}="286515200"
udevinfo -a -p /sys/block/sdb | grep -i model
Gives the following...