systemd Status Update
Nov 19, 2010, 16:02 (4 Talkback[s])
Re-Imagining Linux Platforms to Meet the Needs of Cloud Service Providers
"It has been a while since my last status update on systemd.
Here's another short, incomprehensive status update on what we
worked on for systemd since then.
* Fedora F15 (Rawhide) now includes a split up
/etc/init.d/rc.sysinit (Bill Nottingham). This allows us to keep
only a minimal compatibility set of shell scripts around, and boot
otherwise a system without any shell scripts at all. In fact, shell
scripts during early boot are only used in exceptional cases, i.e.
when you enabled autoswapping (bad idea anyway), when a full
SELinux relabel is necessary, during the first boot after
initialization, if you have static kernel modules to load (which
are not configured via the systemd-native way to do that), if you
boot from a read-only NFS server, or when you rely on
LVM/RAID/Multipath. If nothing of this applies to you can easily
disable these parts of early boot and save several seconds on boot.
How to do this I will describe in a later blog story.
* We have a fully C coded shutdown logic that kills all
remaining processes, unmounts all remaining file systems, detaches
all loop devices and DM volumes and does that in the right way to
ensure that all these things are properly teared down even if they
depend on each other in arbitrary ways. This is not only
considerably faster then the traditional shell hackery for this,
but also a lot safer, since we try to unmount/remount the remaining
file systems with a little bit of brains. This feature is available
via systemctl --force poweroff to the administrator. The --force
controls whether the usual shutdown of all services is run or
whether this is skipped and we immediately shall enter this final C
shutdown logic. Using --force hence is a much safer replacement for
the old /sbin/reboot -f and does not leave dirty file systems
behind. (Thanks to Fabiano Fidencio has his colleagues from
ProFUSION for this)."