After upgrade from Ubuntu 17.10 to 18.04 the bootprocess takes 30s longer than before.
it stops for 30 seconds at the step
Begin: Running /scripts/local-premount
Then it continues.
At first it continued one step further to
scanning for btrfs file systems
so I uninstalled btrfs support, but that didn't help with the problem.
I see no notice of that step neither in dmesg
nor in var/log/boot.log
How can I debug this problem? Can I enable additional logging?