I'm not sure about the problem being getting devices for /dev/dm-*. In Leap 42.1, the disks do not apper as dm-*. They are recognized in /dev/mapper/ddf1*. Getting disks from /dev/dm-* just came in place after I started(restarted) multipath. If I do that, the disks are mapped in /dev/dm-*. But if I don't, the disks are not saw in Leap 42.2 and Tumbleweed, but theu are recognized in Leap 42.1. I have also noted a problem with partition naming. In /dev/mapper the partitions are of the form ddf1_sata_raid1, for example. But in GUI installer, they appear as ddf1_sata_raidp1. There is an extra "p" at the end.