Difference between multipath -ll command and multipath -l command

Question

From the multipath man page http://linux.die.net/man/8/multipath

multipath -l shows the current multipath topology from information fetched in sysfs and the device mapper while multipath -ll shows the current multipath topology from all available information (sysfs, the device mapper, path checkers ...)

Honestly, I cannot think of any case where we would get multipath topologies from places apart from sysfs and device mapper. Can anyone please elaborate why do we have separate command line options for these ?

TIA.

Answer 1

I can not leave comments so I will post this as an answer.

Some device-mapper alternatives may appear, like ddsetup (although on the same syscalls), or you can even use direct syscalls used by device-mapper to achieve the same goals. Thus, you'd have to ask kernel directly via some other syscalls what is the topology.

It sounds exotic, but sometimes you feel like bash layer is extra and so you switch to direct work with the kernel.