I know it is regarded as too early to upgrade from 16.04 to 18.04 but ...
and I am aware of this post:
I nonetheless noticed that on an otherwise successful upgrade the boot time was greatly increased. I was using a SSD hard drive with LVM. Once booted it was fine but it does detract from spending the extra on a SSD.
With "quiet" boot disabled it gave these errors:
"failed to connect to lvmetad" "falling back to device scanning"
where it sat for a while.
I did a fresh install just to be sure it was not just about the "upgrade" but got the same result.
There is reference to a similar problem in the above report that cross-references a bugzilla report on Redhat (an old one) that was not really resolved at that time.
It is not a problem I have had with Debian and I wondered if anyone else had had this problem?
I ended up reinstalling without lvm to get rid of this annoyance. Please note I do have a bit of an odd motherboard, GIGABYTE GA-990X-Gaming SLI.
heathrobinson.