Comment # 3 on bug 1215826 from Felix Miata

(In reply to Tristan Miller from comment #2)
> I noticed when looking up the UUID of the swap device that it was always
> /dev/sdb2 when booting from the 6.4.12 kernel, whereas when booting from the
> 6.5.4 kernel it was sometimes /dev/sda2 and sometimes /dev/sdb2.  So I think
> the real problem here is that the 6.5.4 kernel doesn't assign device names
> in the same consistent manner than 6.4.12 did, so you can't rely on these
> names in the bootloader.

This has been an on-again off-again problem for decades, and one of the reasons
for the long ago switch to using using more reliable descriptors than kernel
names.

> I think that nowadays a fresh install of Tumbleweed will always use the
> device's UUID, but my system was first installed back in 2014 and so was
> still using the old /dev/sdXY-style identifiers.

Back around 10.3 or 11.0 a switch from kernel device names to /dev/disk/by-id/*
was made. I think the switch from those to UUIDs by default was made in 13.2,
which Tumbleweed inherited, or possibly the other way around, when instead of a
13.3 we got Leap and the initial Tumbleweed.

My own installations have long been using primarily LABEL=, IIRC since my
initial use of SUSE, 8.0. 

Note that resume= is an /option/ on Grub's linu lines. It overrides the resume=
that initrds include by default in openSUSE.