Comment # 26 on bug 997637 from Neil Rickert

I realized the mistake on that "pvscan" check.  The major:minor of 8:21 refers
to the encrypted container.  I should, instead, have used 254:0.  That's what
gives more interesting output on my 42.1 system (which does not use lvmetad).

So I tried that, but still got about the same output as before.

Hmm, shouldn't the scan be done by "lvmetad" rather than by "systemd"?  Maybe
that "systemctl" command is checking something that doesn't matter.

On the udev rules:  I'm seeing what Ludwig mentioned.  That is, there is no
mention of "SYSTEMD_WANTS" in that file.  There is a rule:
RUN+="/sbin/lvm pvscan --background --cache --activate ay --major $major
--minor $minor", ENV{LVM_SCANNED}="1"