NO TO SYSVINIT - or initscripts, rather!

Posted Nov 2, 2018 19:11 UTC (Fri) by mchehab (subscriber, #41156)
In reply to: NO TO SYSVINIT - or initscripts, rather! by Cyberax
Parent article: Init system support in Debian

> I wonder if you have an unrelated issue in your systems somewhere.

Yeah, there was indeed an issue: I build kernels with KASAN enabled. That, together with all stuff systemd tries to load and then unload at the initrd disk, made it really slow (it was spending ~30 seconds at initrd). I did a clean custom.target with the minimum stuff, with improved it a lot:

$ ls /etc/systemd/system/custom.target.wants/
anacron.service dbus.service networking.service rsyslog.service systemd-resolved.service thermald.service atd.service inetd.service NetworkManager.service ssh.service systemd-update-utmp-runlevel.service ttyUSB0.service cron.service irqbalance.service ondemand.service systemd-logind.service systemd-user-sessions.service

Also removed an open-iscsi package (with alone saved almost 15 seconds).

After lots of cleanups, I was able to reduce the time for network to start to "just" 1 minute, with KASAN enabled.

Without KASAN, using a vanilla Ubuntu Kernel, it is now booting really quick:

Startup finished in 777ms (kernel) + 2.416s (initrd) + 8.385s (userspace) = 11.579s
custom.target reached after 8.383s in userspace

Discovering it costed me an entire day of work. Doing the same with sysV would be trivial.