Hi,
today I did a d-u that brought me finally a reduction in boot time from 45 s to 15 s.
So the stalling is over. I think it might has to do with the apache packs update that came with, as the systemd-command "blame..." showed me the apache before, consuming most of the time.
Just for your information.
all the way back, on bootup actually I am at 45 s again. I have to investigate further.
I modified forth and back some fstab entries and were sure that the reason is not there.
I'll experimenting xsystemd.automount .
So after testing that, I really oversaw something before writing the initial post above.
But now I have it:
I have a fstab entry for a hd with option "noauto", which I mount manually in case I require:
UUID=dd17993b-43b1-490a-94d2-07b99ba93c3b /data_hd_1 ext4 noauto,user,rw,exec,relatime 0 2 resulting in boot-up time 45 s.
Modifying the line to
#UUID=dd17993b-43b1-490a-94d2-07b99ba93c3b /data_hd_1 ext4 noauto,user,rw,exec,relatime 0 2
testwise and better to
UUID=dd17993b-43b1-490a-94d2-07b99ba93c3b /data_hd_1 ext4 noauto,user,rw,x-systemd.automount,exec,relatime 0 2
results in boot-up time around 15 s.
So
x-systemd.automount
is the solution for me on this kind of disks.