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.