Comment 20 for bug 1611945

I saw the discussion in zfs-discuss and read a bit for fun.

To answer some old questions from what i understood from linked resources:
This bug/deficiency seem to make it impossible to see all drives behind a port multiplier when using links in /dev/disk/by-path/ but not other links, making the drives unadressable by slot.

This can be fixed by patching systemd. Why this haven't been done seems to be summarized here:
https://github.com/systemd/systemd/issues/3943#issuecomment-404996399

The patch submitted here seems to be outdated, later one found here:
https://github.com/sitsofe/systemd/commit/ee26c33ede684138ba9fdc7f286bfa402860aff3

IMHO, the easiest (but not easy) way to add this patch in Ubuntu on your own would be to create an PPA and rebuild systemd from ubuntu with the patch added. Note that you'll be responsible for keeping your systemd-package up to date on your own and that changes can be made upstream that breaks the patch.

It could be added in the official ubuntu package of systemd, but I'm guessing they don't want to add a patch that adds a naming scheme for drives that later might change when the proper fix mentioned last in the first link is implemented.