Hardware RAID passthrough devices
This option can be used to add physical disks behind hardware RAID
controllers when they are not detected automatically, but can be queried
by smartctl through a passthrough device. Leave it empty unless
you need to monitor disks behind such a controller.
For example, /dev/sg0 cciss 0 3 adds three cciss
physical disks numbered 0, 1 and 2 through the /dev/sg0
passthrough device. The final value is the number of disks to add, not the
last disk number.