tl;dr: Why systemd?
What?
- systemd is a system and service manager for Linux, compatible with SysV and LSB init scripts.
- It can act as a drop-in replacement for SysVinit.
- Arch Linux will eventually fully migrate to systemd.
When?
- When it’s ready. For the foreseeable future, both SysVinit and systemd will be supported.
Why?
(From tomegun @ Arch Forums)
- It’s hot-pluggable.
- It tracks all daemons and processes.
- It’s modular.
- It makes better use of udev and dbus.
- It reduces dependencies between daemons.
- It’s easier to sandbox configuration options.
- It’s a cross-distro project.
- It can use distro-independent service files.
- It uses logind to properly manage user sessions.
- It’s faster or just as fast as SysVinit for most users.