Comment 3 for bug 959749

The dm-multipath was built-in in Lucid and became a module at some point. This needs to be added to the d-i section for the kernel build to make it available for the installer.
The device handlers never seem to have been built-in or contained in any d-i file. On the other hand it should not hurt to have them packaged as well (except space considerations on the media, but all four take about 100KB for amd64). And it is likely a bit late to experiment now.

So proposing to add dm-multipath to the md-modules udeb and the device handlers to the scsi-modules udeb.