issue with systemd-udev-settle

[Matthias Bodenbinder <matthias@bodenbinder.de>]

Hi,

I installed debian 8 on one of my PCs and got into trouble with extra long boot times of > 2 min. I found out that it due to systemd-udev-settle.service. My PC is using lvm and that somehow interferes with systemd-udev-settle.service. The web tells that systemd-udev-settle.service is needed for lvm. Nevertheless I deactivated it with
	systemctl mask systemd-udev-settle

The PC is booting fast now and the logical volumne is mounted just fine.  

Q1) So what is the thing about systemd-udev-settle being needed for lvm? Do I miss something?
Q2) Is there a way to set a shorter timeout value for systemd-udev-settle.service? 

Thanks 
Matthias