Comment 2 for bug 1839915

Thanks for filing the bug. I had some probert data that could reproduce as well.

One of the challenges, as you see, is that multipath "partitions" are really additional dm devices, except, they are actual partitions on the underlying disks.

so, you'll have dm2 "partition" on dm0 (mpath device) which is on top of sda which will have an actual sda2.

So curtin generally wants to ignore the mpath device itself, and deal with _one_ path.

We have a couple of options; MAAS currently dumps *all* of the disks it found in the config, and constructs a layout from just *one* of the disks since MAAS and curtin don't *construct* multipath devices (the construction is how the devices are wired up).

Subiquity can also use this method, including all of the paths, but creating partitions/devices against just a single path. Alternatively, we can exclude any of the additional paths after selecting one of the paths and curtin will detect that the underlying disk is part of a multipath and ensure that the target OS has multipath enabled/configured.